add mqtt/homeassistant topics configurable

[bdbogjoe]

related to issue : https://github.com/MaxWinterstein/toogoodtogo-ha-mqtt-bridge/issues/131

[MaxWinterstein]

WOW! Thanks for the contribution!

Did you test this with HA, too? Just scrolling by, some things make me curious like e.g. the intense_fetch state stuff.

Will try to test this in detail asap, but please give me a few days. Having time and energy is hard to find these days...