TUN-4063: Cleanup dependencies between packages.

- Move packages the provide generic functionality (such as config) from `cmd` subtree to top level.
- Remove all dependencies on `cmd` subtree from top level packages.
- Consolidate all code dealing with token generation and transfer to a single cohesive package.

cmd/cloudflared/buildinfo/build_info.go

@@ -2,6 +2,7 @@ package buildinfo
 
 import (
 	"github.com/rs/zerolog"
+	"fmt"
 	"runtime"
 )
 
@@ -25,3 +26,7 @@ func (bi *BuildInfo) Log(log *zerolog.Logger) {
 	log.Info().Msgf("Version %s", bi.CloudflaredVersion)
 	log.Info().Msgf("GOOS: %s, GOVersion: %s, GoArch: %s", bi.GoOS, bi.GoVersion, bi.GoArch)
 }
+
+func (bi *BuildInfo) OSArch() string {
+	return fmt.Sprintf("%s_%s", bi.GoOS, bi.GoArch)
+}