Make clippy a global linter. This means it only runs once per
workspace, which is good because `cargo` handles parallelization
internally. There's no reason to split things out into multiple commands.
Updated the global linter config handling to pass a list of files. This
is needed for clippy and we can just ignore them for the android lints.
Updated the clippy linter to work with crates outside of `gkrust`. For
these crates, we call `cargo clippy` directly and does not filter by
path name. These crates need to be listed in `tools/lint/clippy.yml`,
currently this is only `uniffi-bindgen-gecko-js`, but it's easy to add
more.
Fixed some lint warnings in the `mozlint` package itself.
Differential Revision: https://phabricator.services.mozilla.com/D246488
a4d7085661