Revert: DataSource: Support config CRUD from apiservers (#106996) (#110342)

Revert "DataSource: Support config CRUD from apiservers (#106996)"

This reverts commit eda94a6434.

pkg/tests/apis/datasource/testdata/testdata-create.yaml

@@ -1,17 +0,0 @@
-apiVersion: testdata.datasource.grafana.app/v0alpha1
-kind: DataSource
-metadata:
-  name: sample-testdata
-spec:
-  title: Sample datasource
-  access: proxy
-  isDefault: true
-  jsonData: 
-    key: value
-    hello: 10
-    world: false
-secure:
-  sampleA:
-    create: secret value here # replaced with UID on write
-  sampleB:
-    name: XYZ # reference to a existing secret