Embed the install manifests in flux binary

- add make target for generating the install manifests using kustomize
- embed the generated manifests in flux binary
- the install and bootstrap commands default to using the embedded manifests
- download the install manifests from GitHub only if the install/bootstrap version arg is set

Signed-off-by: Stefan Prodan <stefan.prodan@gmail.com>

cmd/flux/main.go

@@ -115,10 +115,12 @@ func init() {
 }
 
 func NewRootFlags() rootFlags {
-	return rootFlags{
+	rf := rootFlags{
 		pollInterval: 2 * time.Second,
 		defaults:     install.MakeDefaultOptions(),
 	}
+	rf.defaults.Version = "v" + VERSION
+	return rf
 }
 
 func main() {