Overhauled UK focus tree and immersive tank eve#nts for soviet

Nerfs to Soviet Union
- Unemployment spirit nerfed
- Nerfs to Winter offensive
- Nerfed resources in Perm, Southern Urals

Fixed critical french ai issue on historical focuses - will no longer attack germany in 1939.

Tweaked naval defines a bit - experimental.

Canadian focus tree improvements.

Tweaks to the new enhanced Soviet focus tree:
Anti-capitalist diplomacy is now needed for claims on baltic. Shortened great purge by 14 days. Slightly nerfed alluminum available. Added focuses: defense of Leningrad, defense if stalingrad and ’a rifle for every man’.

Fixed player led peace conference option, enable/disable in custom game rules.

Fixed soviet-jap treaty.

Added two new MP game rules: Forced to accept demands on bessarabia and forced historic acceptance if soviet-japanese treaty.

Fixed some portraits for commonwelth and sweden.

Various other bugfixes, thanks to Davewolf and Reichstangle Victor for reporting them!

Hotfixed Commonwelth fighters.

Soviet focus tree additions.
Various bugfixes.