Extend external_bot.py to be able to run compiled bots

[BurnySc2]

In https://github.com/BurnySc2/python-sc2/blob/76e4a435732d4359e5bd9e15b6283a0498e212ca/examples/external_bot.py we can run bots using an external file path.

Extend it to launch a bot.exe (on linux: via wine) so that bot vs bot works as well as human vs bot. This should already be supportet by BotProcess class https://github.com/BurnySc2/python-sc2/blob/76e4a435732d4359e5bd9e15b6283a0498e212ca/sc2/player.py#L124