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/decl_parser.go

@@ -0,0 +1,63 @@
+package pfs
+
+import (
+	"fmt"
+	"io/fs"
+	"path/filepath"
+	"sort"
+
+	"cuelang.org/go/cue/cuecontext"
+)
+
+type DeclParser struct {
+	skip map[string]bool
+}
+
+func NewDeclParser(skip map[string]bool) *DeclParser {
+	return &DeclParser{
+		skip: skip,
+	}
+}
+
+// TODO convert this to be the new parser for Tree
+func (psr *DeclParser) Parse(root fs.FS) ([]*PluginDecl, error) {
+	ctx := cuecontext.New()
+	// TODO remove hardcoded tree structure assumption, work from root of provided fs
+	plugins, err := fs.Glob(root, "**/**/plugin.json")
+	if err != nil {
+		return nil, fmt.Errorf("error finding plugin dirs: %w", err)
+	}
+
+	decls := make([]*PluginDecl, 0)
+	for _, plugin := range plugins {
+		path := filepath.ToSlash(filepath.Dir(plugin))
+		base := filepath.Base(path)
+		if skip, ok := psr.skip[base]; ok && skip {
+			continue
+		}
+
+		dir, _ := fs.Sub(root, path)
+		pp, err := ParsePluginFS(ctx, dir, path)
+		if err != nil {
+			return nil, fmt.Errorf("parsing plugin failed for %s: %s", dir, err)
+		}
+
+		if !pp.CueFile.Exists() {
+			continue
+		}
+
+		decls = append(decls, &PluginDecl{
+			SchemaInterface: pp.Variant,
+			CueFile:         pp.CueFile,
+			Imports:         pp.CUEImports,
+			PluginMeta:      pp.Properties,
+			PluginPath:      path,
+		})
+	}
+
+	sort.Slice(decls, func(i, j int) bool {
+		return decls[i].PluginPath < decls[j].PluginPath
+	})
+
+	return decls, nil
+}