* Ported the project to CMake
  * Android and Mac support dropped for the time
being.
  * Tests, BASS and Discord-RPC are now options
* Restructured and reformated the project.
  * Merged `include` and `src`
  * Renamed `resource` to `data`
  * Renamed various files
  * External libraries headers are no longer included in `src`
  * Replaced header guards with #pragma once
  * Multiple refactors (keywords, headers)
  * Added Qt6 compatibility
* Removed various unused functions and headers
* Reworked AOPacket
  * When content is passed to AOPacket, it should be ensured that the content is already decoded.
  * Encoding/decoding are now static methods.
* Fixed various memory leaks
* Removed animation code for AOImage
  * AOImage is always using static images
* Simplified ChatLogPiece

* italian translation by dev and mandarino

* swap music and character loading

* update all the other translations as well

Also updated the translation files for missing strings and updated the Polish translation.

(Needs review)

Note that there are some strings that had the tr() qualification
removed, and also a LOT of strings that were never wrapped with
tr() to begin with. It will take some work to bring back i18n support.

Due to a countless number of changes made to the core that were not
fully understood, tested, or documented, it was decided to roll
everything back to the last known stable version (2.6.2).

Changes dropped include:
 - Witness needed
 - Shake
 - Frame SFX
 - Multiple custom objections
 - Multithreaded thumbnail generation
 - Looping
 - Various translation additions
 - "Mirror IC"
 - Color in IC log
 - An invocation of clang-format

Next time, work together and split your big fork into independently
testable feature branches.