Build: Nx improvements (#88341)

* feat(frontend): introduce project.json for every workspace to improve caching

* refactor(frontend): use nx tags for grafana dependson

* refactor(frontend): clean up nx tags for packages and plugins

* build(nx): make grafana dependent on cacheable generate icons command

* build(nx): clean up project files

packages/grafana-sql/project.json

@@ -0,0 +1,6 @@
+{
+  "$schema": "../../node_modules/nx/schemas/project-schema.json",
+  "projectType": "library",
+  "tags": ["scope:package", "type:ui"],
+  "targets": {}
+}