Glean-parser

- Raise limit on number of statically-defined lables to 100. ([bug 1702263](https://bugzilla.mozilla.org/show_bug.cgi?id=1702263))
- BUGFIX: Version 2.0.0 of the schema now allows the "special" `glean_.*` ping names for Glean-internal use again.
- Remove support for JWE metric types.

- Add parser and object model support for `rate` metric type. ([bug 1645166](https://bugzilla.mozilla.org/show_bug.cgi?id=1645166))
- Add parser and object model support for telemetry_mirror property. ([bug 1685406](https://bugzilla.mozilla.org/show_bug.cgi?id=1685406))
- Update the Javascript template to match Glean.js expectations. ([bug 1693516](https://bugzilla.mozilla.org/show_bug.cgi?id=1693516))
- Glean.js has updated it's export strategy. It will now export each metric type as an independent module;
- Glean.js has dropped support for non ES6 modules.
- Add support for generating Typescript code. ([bug 1692157](https://bugzilla.mozilla.org/show_bug.cgi?id=1692157))
- The templates added generate metrics and pings code for Glean.js.

- **Experimental:** `glean_parser` has a new subcommand `coverage` to convert raw coverage reports
into something consumable by coverage tools, such as codecov.io
- The path to the file that each metric is defined in is now stored on the
`Metric` object in `defined_in["filepath"]`.

- Leverage the `glean_namespace` to provide correct import when building for Javascript.

- The Kotlin generator now generates static build information that can be passed
into `Glean.initialize` to avoid calling the package manager at runtime.

- Add support for generating Javascript code.
- The templates added generate metrics and pings code for Glean.js.