fs: move CommaSepList and SpaceSepList here from config

fs can't import config so having them there means they are not usable
by rclone core.

fs/config_list.go

@@ -0,0 +1,94 @@
+package fs
+
+import (
+	"bytes"
+	"encoding/csv"
+	"fmt"
+)
+
+// CommaSepList is a comma separated config value
+// It uses the encoding/csv rules for quoting and escaping
+type CommaSepList []string
+
+// SpaceSepList is a space separated config value
+// It uses the encoding/csv rules for quoting and escaping
+type SpaceSepList []string
+
+type genericList []string
+
+func (l CommaSepList) String() string {
+	return genericList(l).string(',')
+}
+
+// Set the List entries
+func (l *CommaSepList) Set(s string) error {
+	return (*genericList)(l).set(',', []byte(s))
+}
+
+// Type of the value
+func (CommaSepList) Type() string {
+	return "[]string"
+}
+
+// Scan implements the fmt.Scanner interface
+func (l *CommaSepList) Scan(s fmt.ScanState, ch rune) error {
+	return (*genericList)(l).scan(',', s, ch)
+}
+
+func (l SpaceSepList) String() string {
+	return genericList(l).string(' ')
+}
+
+// Set the List entries
+func (l *SpaceSepList) Set(s string) error {
+	return (*genericList)(l).set(' ', []byte(s))
+}
+
+// Type of the value
+func (SpaceSepList) Type() string {
+	return "[]string"
+}
+
+// Scan implements the fmt.Scanner interface
+func (l *SpaceSepList) Scan(s fmt.ScanState, ch rune) error {
+	return (*genericList)(l).scan(' ', s, ch)
+}
+
+func (gl genericList) string(sep rune) string {
+	var buf bytes.Buffer
+	w := csv.NewWriter(&buf)
+	w.Comma = sep
+	err := w.Write(gl)
+	if err != nil {
+		// can only happen if w.Comma is invalid
+		panic(err)
+	}
+	w.Flush()
+	return string(bytes.TrimSpace(buf.Bytes()))
+}
+
+func (gl *genericList) set(sep rune, b []byte) error {
+	if len(b) == 0 {
+		*gl = nil
+		return nil
+	}
+	r := csv.NewReader(bytes.NewReader(b))
+	r.Comma = sep
+
+	record, err := r.Read()
+	switch _err := err.(type) {
+	case nil:
+		*gl = record
+	case *csv.ParseError:
+		err = _err.Err // remove line numbers from the error message
+	}
+	return err
+}
+
+func (gl *genericList) scan(sep rune, s fmt.ScanState, ch rune) error {
+	token, err := s.Token(true, func(rune) bool { return true })
+	if err != nil {
+		return err
+	}
+	return gl.set(sep, bytes.TrimSpace(token))
+}