Turn on ripgrep by default

[jacob314]

Ripgrep is surfaced as an option but not enabled by default. This should reduce memory usage and increase search speed significantly.
Need to verify fallback is graceful for users that cannot use ripgrep.
Need to verify it does not regress quality due to differences in what matches are shown.

[rwst]

None of the ripgrep versions are installable / downloadable atm.