restructure rcloud-base as a single base controller (#37)

* restructure rcloud-base as a single base controller
* updated master.rest
* moved sentry from internal to pkg as it is used by relay
* removing unused rpc and it's dependencies
* Fix usermgmt tests
* Don't redefine variables in rest file
Co-authored-by: Abin Simon <abin.simon@rafay.co>

pkg/controller/util/string.go

@@ -0,0 +1,22 @@
+package util
+
+// ContainsString checks if string exists in slice
+func ContainsString(slice []string, s string) bool {
+	for _, item := range slice {
+		if item == s {
+			return true
+		}
+	}
+	return false
+}
+
+// RemoveString removes string from slick
+func RemoveString(slice []string, s string) (result []string) {
+	for _, item := range slice {
+		if item == s {
+			continue
+		}
+		result = append(result, item)
+	}
+	return
+}