Feat/stackittpr 442 depedency cooldowns (#1125)

* feat(deps) add 7d dependency cooldown for external deps, 0 for internal

* feat(deps) rm renovate config and workflow

* fix(deps) manage internal vs external dependencies via cooldown.exclude

Author: cgoetz-inovex

.github/dependabot.yml

@@ -0,0 +1,15 @@
+version: 2
+updates:
+  - package-ecosystem: "gomod"
+    directory: "/" 
+    schedule:
+      interval: "daily"
+    cooldown:
+      default-days: 7
+      exclude: ["github.com/stackitcloud*"]
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+    cooldown:
+        default-days: 7