Adds the option to require smtp connections to use STARTTLS
authentication. This is distinct from SSL and TLS and usually shares a
port with unencrypted connections. This change enables starttls for
the connection and makes it required. This appears as it's own
security setting in the email configuration.

fixes: https://github.com/metabase/metabase/issues/4272

https://github.com/metabase/metabase/issues/3715
Liquibase has been rechecking the jar signature for each migration
file, resulting in slow startup times.

characters [ci drivers]

* QB modes, actions, and drill throughs.

* Refactor drill throughs + misc bug fixes

* Port sort action to drills

* Smarter 'view this/these' name

* Scalar hover state

* QB actions: don't skip action selection screen unless the action is marked as 'default'

* Fix flow errors

* Fix drills

* Show "This X's Ys" for FKs

* Prevent qb from uneccesary push states

* Don't show (fk) breakout fields that have already been broken out

* Fix 'drill into this' unit

* Cleanup timeseries footer

* Cleanup qb selectors

* Namespace all qb actions

* Make modes dependent on previously run card

* More timeseries footer cleanup

* Fix table crash

* Make breakout legend clickable

* Fix datagrid pivot test

* Flow + lint

[ci drivers]