Do not use the AC3 maven server

It happens to be down sometimes.
Move passwords.useSalt to secret.yml
Do not create lang folder on first run
Improve account importing wizard
Finish migrating to Public Domain

* Remove license headers from all files authored by LucasEasedUp
* Change license in pom.xml
Move passwords.disable to secret.yml
Allow prefixing allowedCommands with a slash
Add config get/set path completion by pressing TAB
Disable TabAPI completely if hideFromTabList is set to false
Some fixes and improvements
Add password complexity checks
Refactor code
Remove usage notes from commands

They are pretty useless.
Add Polish donation link