Ganglia sink using libganglia.so directly (#35)

* Add sink directly using libganglia.so

* Remove unneeded confuse header

* add submodule init to build action

* add submodule init to runonce action

* add installation og ganglia to runonce

* add installation of ganglia to runonce

* add installation of ganglia to runonce

* libconfuse not required

* Remove ganglia submodule

* Remove ganglia.h

* Add Makefile to help creating the libganglia.so link

* Fix cgo header

* Rename new Ganglia sink to 'libgangliaSink'

* Add documentation for libgangliaSink

* Extend make buildsystem with find&symlink helper for libgangliaSink

* Add metric renaming function

* Add build tag 'ganglia' and create corresponding files

sinks/libgangliaSink_disabled.go

@@ -0,0 +1,29 @@
+//go:build !ganglia
+
+package sinks
+
+import (
+	"encoding/json"
+	"errors"
+
+	lp "github.com/ClusterCockpit/cc-metric-collector/internal/ccMetric"
+)
+
+type LibgangliaSink struct {
+	sink
+}
+
+func (s *LibgangliaSink) Init(config json.RawMessage) error {
+	return errors.New("sink 'libganglia' not implemented, rebuild with tag 'ganglia'")
+}
+
+func (s *LibgangliaSink) Write(point lp.CCMetric) error {
+	return errors.New("sink 'libganglia' not implemented, rebuild with tag 'ganglia'")
+}
+
+func (s *LibgangliaSink) Flush() error {
+	return errors.New("sink 'ganglia' not implemented, rebuild with tag 'ganglia'")
+}
+
+func (s *LibgangliaSink) Close() {
+}