Provide better testing for Tor Browser not breaking important websites (Twitter/Github etc.)

We recently had to deal with Twitter being hardly usable for Tor Browser users due to a bug in our code (see legacy/trac#16450 (moved) and legacy/trac#21555 (moved)). We might want to have some tests informing us as early as possible if such a breakage happens. Selenium might be a good tool for writing such tests, maybe Marionette as well.

added ReleaseTrainMigration in Legacy / Trac component::applications/quality assurance and testing in Legacy / Trac owner::cypherpunks in Legacy / Trac parent::33654 in Legacy / Trac priority::medium in Legacy / Trac severity::normal in Legacy / Trac sponsor::58 in Legacy / Trac status::new in Legacy / Trac type::enhancement in Legacy / Trac labels

Trac:
Cc: N/A to boklm

Trac:
Cc: boklm to boklm, brade, mcs

Currently, it's impossible to sign up to Github with Tor Browser.

Trac:
Username: indigotime

Release Train Migration.

Trac:
Keywords: N/A deleted, ReleaseTrainMigration added

Adding S58 on testsuite tickets.

Trac:
Sponsor: N/A to Sponsor58

Grouping all TBB testing tickets under S58O1.1

These will need to be reviewed and re-classified

Trac:
Parent: N/A to legacy/trac#33654 (moved)

mentioned in issue legacy/trac#22144 (moved)

mentioned in issue legacy/trac#33654 (moved)

moved from legacy/trac#22058 (moved)

added Feature label and removed 1 deleted label

added Release Train Migration label and removed 1 deleted label

unassigned @cypherpunks

added Roadmap::Future label