ref: one codebase for hover tooltip and freezed tooltip

- rename variables for URL template, use templateSrv to render URL links
- fix visibility of tooltip items and url template help popup whe the light theme is used
- rework Tooltip settings pane, organize tooltip editor fields
- rename properties in panel config, implement migration logic for legacy configuration
- close button for the frozen tooltip
- use relative positioning for proper page scrolling

dist/extra_series_format.js

@@ -1,28 +0,0 @@
-"use strict";
-
-System.register([], function (_export, _context) {
-  "use strict";
-
-  var ExtraSeriesFormat, ExtraSeriesFormatValue;
-
-  _export({
-    ExtraSeriesFormat: void 0,
-    ExtraSeriesFormatValue: void 0
-  });
-
-  return {
-    setters: [],
-    execute: function () {
-      (function (ExtraSeriesFormat) {
-        ExtraSeriesFormat["Date"] = "Date";
-        ExtraSeriesFormat["Raw"] = "Raw";
-      })(ExtraSeriesFormat || _export("ExtraSeriesFormat", ExtraSeriesFormat = {}));
-
-      (function (ExtraSeriesFormatValue) {
-        ExtraSeriesFormatValue["Date"] = "YYYY/MM/DD/HH_mm_ss";
-        ExtraSeriesFormatValue["Raw"] = "";
-      })(ExtraSeriesFormatValue || _export("ExtraSeriesFormatValue", ExtraSeriesFormatValue = {}));
-    }
-  };
-});
-//# sourceMappingURL=extra_series_format.js.map