- moved 'default to current deck when adding' into prefs
- move some profile options into the collection config, so they're
undoable and will sync. There is (currently) no automatic migration
from the old profile settings, meaning users will need to set the
options again if they've customized them.
- tidy up preferences.py
- drop the deleteMedia option that was not exposed in the UI
- Rework V2 upgrade so that it no longer resets cards in learning,
or empties filtered decks.
- V1 users will receive a message at the top of the deck list
encouraging them to upgrade, and they can upgrade directly from that
screen.
- The setting in the preferences screen has been removed, so users
will need to use an older Anki version if they wish to switch back to
V1.
- Prevent V2 exports with scheduling from being importable into a V1
collection - the code was previously allowing this when it shouldn't
have been.
- New collections still default to v1 at the moment.
Also add helper to get map of decks and deck configs, as there were
a few places in the codebase where that was required.
- use the TimestampSecs newtype instead of raw i64s
- use FixedOffset instead of a minutes_west offset
- check localOffset each time the timing is calculated, and set it
if it's stale - even for v1.
- check for and fix missing rollover when calculating timing
- stop explicitly passing localOffset in the sync/start call
