Add/Improve SQLite compatiblity

[Soapy7261]

This PR aims to add or improve compatibility/usage for SQLite databases.
While the BlueMap base already technically supports SQLite via the use of custom drivers, certain parts (such as the sql.php script) do not.

Compatibility todo:

• sql.php
• BlueMap base

Options that should be added, in order of how important they probably are (None of them should require any internal code changes?):

• Option for enabling WAL (PRAGMA journal_mode = WAL;, definitely most important imo)
• Option(s?) for increasing cache size (PRAGMA cache_size = -20000;, negative means kilobytes, so 20MB cache, should be configurable though)
• Option for decreasing syncs (PRAGMA synchronous = NORMAL;, only safe to use with WAL, might lose the latest transactions on sudden power loss, but shouldn't corrupt the DB itself)
• Option for storing temporary tables in RAM (PRAGMA temp_store = memory;, not necessary with proper indexing)

^ All options can be added by the user now

Other todo:

• Limit max-connections to 1 if using SQLite (Using more doesn't have any performance benefit in my testing, and is just more likely to hit annoying SQLITE_BUSY errors, even if using WAL)
• All @TODOs solved

[Soapy7261]

Comment for future self: This should probably specify it'll (most likely) require an absolute path instead of a relative path

[Soapy7261]

Should also specify that you'll need an extra driver on Windows for SQLite on PHP

[TBlueF]

Probably wrong repo for this?

nope, correct repo

My thoughts about the PRAGMA statements:
If these get implemented then i think i would like them to be somehow completely configurable .. as in ..
Some configuration e.g. similar to connection-properties that allows the user to specify key and value of each pragma they want to configure.

I also don't like the thought of having sqlite-specific settings in the sql.conf that are being ignored by all other database-types ..
Maybe we need to split SQL and Sqlite storage-types and make a separate config-template for sqlite for this.
max-connections could then also be hidden and default to 1 in the sqlite config-template.

[Soapy7261]

(noted!)
When I last used SQLite, it required a separate driver jar and proper driver-class specification, if we are going to make a separate sqlite.conf, maybe a library should be built-in for it to work natively?

[TBlueF]

No, bluemap doesn't include any of the sql-drivers.
If we include one, we need to include all of them,
and i don't think i want to do that ^^

[Soapy7261]

Oh, I didn't realize none were bundled.. oops?
I'll add a valid JDBC driver URL for SQLite to the sqlite.conf comments then (similar to how mariadb is already commented)

[Soapy7261]

While technically less configurable, I don't think there's really any reason to include the whole connection-url as a config option for SQLite, as it's kind of confusing as-is with like jdbc:sqlite:file:bluemap/bluemap.db, and any options I've seen come after the jdbc:sqlite:file, so maybe the option should just be like filename and used like bluemap/bluemap.db or something? You could still pass flags at the end too.
Perhaps it's better that way?

[Soapy7261]

Works for SQLite now and respects all PRAGMAs I tested, solving all @TODOs is all that's left (I think?)

[Soapy7261]

Might also make sense to have a config option to run a PRAGMA integrity_check (or maybe PRAGMA quick_check?) to make sure the DB isn't corrupt before trying to use it.
Or just handle PRAGMA (integrity)/(quick)_check