Get SQL databases working again

[TheLimeGlass]

Description

• Adds H2 as a configurable database. Will probably make default eventually or maybe in this pull request?
• Removes SQLibrary and adds https://github.com/brettwooldridge/HikariCP as the main SQL wrapper.
• Revamped API for better registration and handling of JDBC Java drivers.
• Added a commit changes option which is essentially how Skript used to operate. Changed the JDBC standard to auto commit after every edit (Make the 5-min variable saving period configurable #2007). This is standard and better for performance. Skript didn't for some reason. I speculate it was to allow MySQL to sync with other servers, so either way it's an option now.

Perks

• Better configuration options with HikariCP.
• Way better performance with HikariCP.
• Easier implementation and not relying on a small project like SQLibary.
• Thread pooling potential with HikariCP.
• This new API design allows for quite literally any JDBC implementation database.
• Uses the SpigotLibraryLoader to load the resources at runtime rather than shadowing into the jar.

TODO

• Test MySQL.
• Test SQLite.
• Test H2.
• Run beta testing in the SkriptLang Discord.
• Adds tests.
• In H2 use H2's MERGE INTO instead of INSERT.
• Forgot to add a check that HikariCP classes were loaded by SpigotLibraryLoader.
• Rename SQLStorage to something with JDBC reference, maybe JdbcStorage as it's not only SQL anymore.
• Test that monitor changes still do something.
• Attach a SkriptAddon instance to the registration, so Skript knows where a storage is coming from.
• Investigate if this solves Critical Bug with List-Variables #2022

Optional

• Write up an API tutorial for registering custom storage types.
• Document all the possible options for databases or have annotations for a documentation system.
• See if Skript could handle async and multithreading now that the database has the possibility.
• Maybe add MongoDB support More DataBase support ? MongoDB for example #1787
• Change the existing behavior of dumping every variable into ram on server start.

Notes:

• Should we just remove SQLite support? It's not like anyone is using it right now, it doesn't work currently.
• H2 is a flat file SQL implementation that supports asynchronous operations and multi threaded unlike SQLite in both those regards.
• This does not impact anything to do with the default flat file CSV.
• This mainly only affects JDBC driver databases. The rework is still a viable experiment started by bensku https://github.com/SkriptLang/Skript/tree/feature/variables2

Testing and using this jar

To test this experimental feature out, go to the "checks" tab and then click a Java version on the side and then click the nightly artifacts to get a built jar of the latest commit.

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Target Minecraft Versions: any
Requirements: none
Related Issues: #1168, #2007, #1478 and #3948

[Pikachu920]

could you push the SkriptLang branch to your fork, then do the work there? once things are ready you can open a PR from that branch to SkriptLang

[Pikachu920]

I guess I'm confused why we'd merge into enhancement/sql instead of having your work on your fork's branch and then you can open a PR from the fork branch to dev/feature

[sovdeeth]

See existing change requests from pickle at previous pr, too: #5646 (review)

[sovdeeth]

shouldn't be in this pr