build: disable tracing support for gRPC

The goal is to be able to reenable full dead code elimination that is
prevented by non-constant calls to reflect.MethodByName(). There are
many other culprits for this:

```
 08:04 ❱ go  build -o /dev/null -tags release,grpcnotrace -ldflags=-dumpdep  .  |& go run github.com/aarzilli/whydeadcode@latest
github.com/go-playground/validator/v10.tryCallValidateFn reachable from:
         github.com/go-playground/validator/v10.isValidateFn
         github.com/go-playground/validator/v10.isValidateFn·f
         github.com/go-playground/validator/v10.map.init.11
         github.com/go-playground/validator/v10.bakedInValidators
         github.com/go-playground/validator/v10.New
         akvorado/common/helpers.init.1
         akvorado/common/helpers..inittask
         go:main.inittasks
         _

github.com/expr-lang/expr/builtin.get reachable from:
         github.com/expr-lang/expr/builtin.get·f
         github.com/expr-lang/expr/builtin..stmp_53
         github.com/expr-lang/expr/builtin..stmp_0
         github.com/expr-lang/expr/builtin.init
         github.com/expr-lang/expr/builtin..inittask
         go:main.inittasks
         _

github.com/expr-lang/expr/checker/nature.Nature.All reachable from:
         type:github.com/expr-lang/expr/checker/nature.Nature
         type:func() github.com/expr-lang/expr/checker/nature.Nature
         type:github.com/expr-lang/expr/ast.Node
         type:github.com/expr-lang/expr/vm.Program
         type:*github.com/expr-lang/expr/vm.Program
         type:akvorado/outlet/core.ExporterClassifierRule
         type:[]akvorado/outlet/core.ExporterClassifierRule
         type:akvorado/outlet/core.Configuration
         type:akvorado/cmd.OutletConfiguration
         type:[]akvorado/cmd.OutletConfiguration
         type:akvorado/cmd.OrchestratorConfiguration
         type:*akvorado/cmd.OrchestratorConfiguration
         internal/abi..dict.TypeFor[akvorado/cmd.OrchestratorConfiguration]
         reflect..dict.TypeFor[akvorado/cmd.OrchestratorConfiguration]
         akvorado/cmd.init.6.orchestratorClickHouseMigrationHook.func2
         akvorado/cmd.init.6.orchestratorClickHouseMigrationHook.func2·f
         akvorado/cmd.init.6
         akvorado/cmd..inittask
         go:main.inittasks
         _

text/template.(*state).evalField reachable from:
         text/template.(*state).evalFieldChain
         text/template.(*state).evalCommand
         text/template.(*state).evalPipeline
         text/template.(*state).walk
         text/template.(*Template).execute
         akvorado/console/authentication.(*Component).UserAuthentication.func1
         akvorado/console/authentication.(*Component).UserAuthentication
         type:*akvorado/console/authentication.Component
         akvorado/cmd.consoleStart
         akvorado/cmd.init.func3
         akvorado/cmd.init.func3·f
         akvorado/cmd..stmp_2
         akvorado/cmd.init
         akvorado/cmd..inittask
         go:main.inittasks
         _

gorm.io/gorm/schema.ParseWithSpecialTableName reachable from:
         gorm.io/gorm.(*DB).assignInterfacesToValue
         gorm.io/gorm.(*DB).FirstOrInit
         type:*gorm.io/gorm.DB
         type:akvorado/console/database.Component
         akvorado/cmd.consoleStart
         akvorado/cmd.init.func3
         akvorado/cmd.init.func3·f
         akvorado/cmd..stmp_2
         akvorado/cmd.init
         akvorado/cmd..inittask
         go:main.inittasks
         _

gorm.io/gorm/schema.ParseWithSpecialTableName reachable from:
         gorm.io/gorm.(*DB).assignInterfacesToValue
         gorm.io/gorm.(*DB).FirstOrInit
         type:*gorm.io/gorm.DB
         type:akvorado/console/database.Component
         type:*akvorado/console/database.Component
         akvorado/cmd.consoleStart
         akvorado/cmd.init.func3
         akvorado/cmd.init.func3·f
         akvorado/cmd..stmp_2
         akvorado/cmd.init
         akvorado/cmd..inittask
         go:main.inittasks
         _

github.com/expr-lang/expr/vm/runtime.FetchMethod reachable from:
         github.com/expr-lang/expr/vm.(*VM).Run
         github.com/expr-lang/expr/vm.Run
         akvorado/outlet/core.(*ExporterClassifierRule).exec
         akvorado/outlet/core.(*Component).classifyExporter
         akvorado/outlet/core.(*worker).enrichFlow
         akvorado/outlet/core.(*worker).processIncomingFlow.func1
         akvorado/outlet/core.(*worker).processIncomingFlow
         akvorado/outlet/core.(*worker).processIncomingFlow-fm
         akvorado/outlet/core.(*Component).newWorker
         akvorado/outlet/core.(*Component).newWorker-fm
         akvorado/outlet/core.(*Component).Start
         type:*akvorado/outlet/core.Component
         akvorado/cmd.outletStart
         akvorado/cmd.init.func7
         akvorado/cmd.init.func7·f
         akvorado/cmd..stmp_6
         akvorado/cmd.init
         akvorado/cmd..inittask
         go:main.inittasks
         _
```

For gorm, we have https://github.com/go-gorm/gorm/pull/7643. We could
replace text/template by something else as our usage is quite light. For
validator, it may be addressable upstream by disallowing calls to
configurable validator function through a tag. For expr, it looks more
complex.

Then, regression should be detected by CI.

Makefile

@@ -64,7 +64,7 @@ all: fmt lint all-indep ; $(info $(M) building executable…) @ ## Build program
          $(if $(filter arm64,$(TARGETARCH)),GOARM64=$(if $(findstring .,$(TARGETVARIANT)),$(TARGETVARIANT),$(TARGETVARIANT:%=%.0)),\
          $(if $(filter arm,$(TARGETARCH)),GOARM=$(TARGETVARIANT:v%=%)))) \
 	   $(GO) build \
-		-tags release \
+		-tags release,grpcnotrace \
 		-ldflags '-X $(MODULE)/common/helpers.AkvoradoVersion=$(VERSION)' \
 		$(BUILD_ARGS) \
 		-o bin/$(basename $(MODULE)) .