Folders: Able to fetch folders available for user as "shared" folder (#77774)

* Folders: Show folders user has access to at the root level

* Refactor

* Refactor

* Hide parent folders user has no access to

* Skip expensive computation if possible

* Fix tests

* Fix potential nil access

* Fix duplicated folders

* Fix linter error

* Fix querying folders if no managed permissions set

* Update benchmark

* Add special shared with me folder and fetch available non-root folders on demand

* Fix parents query

* Improve db query for folders

* Reset benchmark changes

* Fix permissions for shared with me folder

* Simplify dedup

* Add option to include shared folder permission to user's permissions

* Fix nil UID

* Remove duplicated folders from shared list

* Only left the base part

* Apply suggestions from code review

Co-authored-by: Sofia Papagiannaki <1632407+papagian@users.noreply.github.com>

* Add tests

* Fix linter errors

---------

Co-authored-by: Sofia Papagiannaki <1632407+papagian@users.noreply.github.com>

pkg/services/folder/folderimpl/store_fake.go

@@ -9,6 +9,7 @@ import (
 type fakeStore struct {
 	ExpectedChildFolders  []*folder.Folder
 	ExpectedParentFolders []*folder.Folder
+	ExpectedFolders       []*folder.Folder
 	ExpectedFolder        *folder.Folder
 	ExpectedError         error
 	ExpectedFolderHeight  int
@@ -55,3 +56,7 @@ func (f *fakeStore) GetChildren(ctx context.Context, cmd folder.GetChildrenQuery
 func (f *fakeStore) GetHeight(ctx context.Context, folderUID string, orgID int64, parentUID *string) (int, error) {
 	return f.ExpectedFolderHeight, f.ExpectedError
 }
+
+func (f *fakeStore) GetFolders(ctx context.Context, orgID int64, uids []string) ([]*folder.Folder, error) {
+	return f.ExpectedFolders, f.ExpectedError
+}