Do codegen and check no-diff of all (non-blacklisted) CUE->TS codegen during CI (#39922)

* Add file blacklist to `grafana-cli cue gen-ts` cmd

* Add CI step checking all cuetsification is done

* Add dummy command to make the next one fail

* Generate drone bits

* Check diff output failure

* Echo list of untracked files, for failure locality

* Move git cleanness checking into script

* Blacklist of cue files is complete and correct

* Remove news panel plugin from cuetsify blacklist

* Dummy commit, check that untracked gen still fail

* Tie off remaining errors

* Re-add barchart to blacklist
* Remove file left around by earlier pipeline
* Commit generated news models.gen.ts

* Include eslint as part of cuetsified output gen

* Update pkg/cmd/grafana-cli/commands/cuetsify_command.go

Co-authored-by: Ashley Harrison <ashley.harrison@grafana.com>

* Update scripts/drone/steps/lib.star

Co-authored-by: Maria Alexandra <239999+axelavargas@users.noreply.github.com>

* Update drone.yml

* Last fix on .drone.yml

Co-authored-by: Ashley Harrison <ashley.harrison@grafana.com>
Co-authored-by: Maria Alexandra <239999+axelavargas@users.noreply.github.com>

scripts/clean-git-or-error.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+set -e
+
+# Checks that a git working tree is clean. Exit 0 if it is, or exit 1 with a list of
+# dirty files - including modifications, removals, and untracked+unignored files.
+
+# Primarily intended for ensuring in CI that codegen operations are a no-op/have
+# already been performed.
+
+STAT="$(git status --porcelain 2>/dev/null)"
+if [ -z "$STAT" ]
+then
+    exit 0
+else
+    echo "$STAT"
+    exit 1
+fi
+
+# For safekeeping, alternative commands that meet a similar goal (in case the
+# above approach ends up being problematic)
+# 
+# List modified/removed files and exit nonzero if any exist:
+# git diff --stat --exit-code
+#
+# List untracked files, and exit nonzero if any exist:
+# git ls-files --others --exclude-standard',
+# u="$(git ls-files --others --exclude-standard)" && test -z "$u"