Prometheus: monaco-based query-editor-field, first step (#37251)

* prometheus: add monaco-based query-field

for now it is behind a feature-flag

* added new trigger character

* better separate grafana-specifc and prom-specific code

* better styling

* more styling

* more styling

* simpler monaco-import

* better imports

* simplified code

* simplified type imports

* refactor: group completion-provider files together

* renamed type

* simplify type-import

Co-authored-by: Piotr Jamróz <pm.jamroz@gmail.com>

* handle no-metric-name autocompletes

* updated comment

Co-authored-by: Piotr Jamróz <pm.jamroz@gmail.com>

package.json

@@ -272,12 +272,16 @@
     "jquery": "3.5.1",
     "json-source-map": "0.6.1",
     "jsurl": "^0.1.5",
+    "lezer": "0.13.5",
+    "lezer-promql": "0.20.0",
+    "lezer-tree": "0.13.2",
     "lodash": "4.17.21",
     "logfmt": "^1.3.2",
     "lru-cache": "^5.1.1",
     "memoize-one": "5.1.1",
     "moment": "2.29.1",
     "moment-timezone": "0.5.33",
+    "monaco-promql": "^1.7.2",
     "mousetrap": "1.6.5",
     "mousetrap-global-bind": "1.1.0",
     "ol": "^6.5.0",