Glean-parser

- **Breaking change:** glinter errors found during the `translate` command will
now return an error code. glinter warnings will be displayed, but not return
an error code.
- `glean_parser` now produces a linter warning when `user` lifetime metrics are
set to expire. See [bug
1604854](https://bugzilla.mozilla.org/show_bug.cgi?id=1604854) for additional
context.

- **Breaking change:** The regular expression used to validate labels is
stricter and more correct.
- Add more information about pings to markdown documentation:
- State whether the ping includes client id;
- Add list of data review links;
- Add list of related bugs links.
- `glean_parser` now makes it easier to write external translation
functions for different language targets.
- BUGFIX: `glean_parser` now works on 32-bit Windows.

- Dropped the `inflection` dependency.
- Constrained the `zipp` and `MarkupSafe` transitive dependencies to versions
that support Python 3.5.

- BUGFIX: Fix rendering of first element of reason list.

- BUGFIX: Reason codes are displayed in markdown output for built-in
pings as well.
- BUGFIX: Reason descriptions are indented correctly in markdown
output.
- BUGFIX: To avoid a compiler error, the `JvmName` annotation isn't
added to private members.

- **Breaking Change (Java API)** Have the metrics names in Java match the names
in Kotlin. See [Bug
1588060](https://bugzilla.mozilla.org/show_bug.cgi?id=1588060).
- The reasons a ping are sent are now included in the generated markdown
documentation.