Codegen: Isolate schema generation code (#98742)

* Create go.mod files for plugins and core kinds

* Update go work and main go.mod dependencies

* Update pfs import

* Missing update of pfs dependency

* Remove fixed cuelang dependency

* Update codeowners

* Update workspace

* Update Dockerfile

* Missing go.mod codeowner

* Use intermediate kin-openapi dependency to make all workspaces to work

pkg/plugins/codegen/pfs/plugin.go

@@ -0,0 +1,22 @@
+package pfs
+
+import (
+	"cuelang.org/go/cue"
+	"cuelang.org/go/cue/ast"
+)
+
+// ParsedPlugin represents everything knowable about a single plugin from static
+// analysis of its filesystem tree contents, as performed by [ParsePluginFS].
+//
+// Guarantees described in the below comments only exist for instances of this
+// struct returned from [ParsePluginFS].
+type ParsedPlugin struct {
+	// Properties contains the plugin's definition, as declared in plugin.json.
+	Properties Metadata
+	CueFile    cue.Value
+	Variant    SchemaInterface
+
+	// CUEImports lists the CUE import statements in the plugin's grafanaplugin CUE
+	// package, if any.
+	CUEImports []*ast.ImportSpec
+}