Support for VERSION tag

[Baklap4]

Suggestion

Within the Ultrastar community we've decided upon a common format. This can be found on our website.
One of the new tags introduced for compatibility reasons is the #VERSION tag.

We can use this tag to determine which features we want to use as dictated by the source.

As seen on the website:

The version attribute helps the game and apps to understand how uptodate a song file is and how it should be treated. Ideally all txt files will be upgraded to the latest version. The value are version numbers according to semantic versioning. Song Editors, Managing tools or txt-hostings should set this automatically.

Todo

• Implement the version tag. Details about each version can be found here and to have a list of tags available in each version can be found here

Use case

• Gradually introduce new features which come in new format versions
• Have a standard way to determine what features to enable for the specific txt in question instead of best effort

Extra info/examples/attachments

Our versions will start with this structure
0.1.0 -> Bare Minimum, Minimum vial product (mvp)
0.2.0 -> Introduce the tags we currently have
0.3.0 -> Deprecate old # tags we don't wanna use (duplicates, technical not nessecary)
1.0.0 -> Removal of deprecated tags and final list of currently used tags (2023)
1.1.0 -> First new features we want to introduce, deprecated #mp3 and chaotic time units (2023)
~1.2.0 -> more new features (2024)
2.0.0 -> Removal of #MP3 and introduce unified time units (=doing breaking changes) (2025)

also linking the vocaluxe issue: Vocaluxe/Vocaluxe#628 just for reference