schema: Migrate from scuemata to thema (#49805)

* Remove crufty scuemata bits

Buhbye to: cue/ dir with old definitions, CI steps for checking unnecessary
things, and the original dashboard scuemata file.

* Remove grafana-cli cue subcommand

* Remove old testdata

* Don't swallow errors from codegen

* Small nits and tweaks to cuectx package

* WIP - refactor pluggen to use Thema

Also consolidate the embed.FS in the repo root.

* Finish halfway rename

* Convert all panel models.cue to thema

* Rewrite pluggen to use Thema

* Remove pkg/schema, and trim command

* Remove schemaloader service and usages

Will be replaced by coremodel-centric hydrate/dehydrate system Soon™.

* Remove schemaloader from wire

* Remove hangover field on histogram models.cue

* Fix lint errors, some vestiges of trim service

* Remove unused cuetsify cli command

pkg/server/wire.go

@@ -78,7 +78,6 @@ import (
 	"github.com/grafana/grafana/pkg/services/queryhistory"
 	"github.com/grafana/grafana/pkg/services/quota"
 	"github.com/grafana/grafana/pkg/services/rendering"
-	"github.com/grafana/grafana/pkg/services/schemaloader"
 	"github.com/grafana/grafana/pkg/services/search"
 	"github.com/grafana/grafana/pkg/services/searchV2"
 	"github.com/grafana/grafana/pkg/services/secrets"
@@ -190,7 +189,6 @@ var wireBasicSet = wire.NewSet(
 	contexthandler.ProvideService,
 	jwt.ProvideService,
 	wire.Bind(new(models.JWTService), new(*jwt.AuthService)),
-	schemaloader.ProvideService,
 	ngalert.ProvideService,
 	librarypanels.ProvideService,
 	wire.Bind(new(librarypanels.Service), new(*librarypanels.LibraryPanelService)),