More clear state flags for OCE states

[sticks-stuff]

Most people in OCE don't even know what their state flag is, much less recognize it in an overlay.

I've replaced these somewhat useless state flags in AUS with Kaiza's custom state icons, which have been commonplace in AUS smash streams for a few years now. I've also designed some for NZ regions as well.

Note that in cases where there are active locals, I've put the city over the region for those players since that's generally the identity of the scene, so:

WKO -> HAM
CAN -> CHC
OTA -> DUN
MWT -> PMN
TKI -> NPL
NTL -> WRE
BOP -> TRG

Bay of Plenty is definitely the most complex, as both Rotorua and Tauranga has had locals in the past. However, there are currently no locals in either region, and Tauranga is 3x the size of Rotorua. Worst case scenario, it's a little odd in the case that somehow there ends up being both Tauranga and Rotorua locals.

3 letter abbreviations are derived from my own knowledge of what Kiwi's would know as each region - plus https://service.unece.org/trade/locode/nz.htm in cases where I didn't really know (just New Plymouth, Whangārei, Tauranga).

[sticks-stuff]

As requested by @joaorb64, this might work better if/when there are custom country/state flags, as the flags in TSH come from a different project that is automated (I was unaware of this). As such, I've updated this PR to move the flags to user_data/custom_flag as suggested, and have marked this PR as a draft until support for custom state/country flags is created.