Add experimental SQLite support to enable in-browser WASM Omeka S playground

[erseco]

This PR adds experimental SQLite support to Omeka S.

This work was not done as a convenience change. It became necessary to build an Omeka S Playground comparable in spirit to WordPress Playground: a version of Omeka S that runs entirely in the browser through WebAssembly, with no traditional server-side installation required.

That playground is already being used here:

• live Omeka S WASM demo: https://ateeducacion.github.io/omeka-s-playground
• source code

Why this matters:

• It makes Omeka S much easier to try, teach, demo, and test.
• It lowers the barrier for first contact with the platform.
• It enables ephemeral and reproducible environments for experimentation.
• It opens the door to browser-based demos, workshops, documentation examples, and QA scenarios.

This SQLite support is the foundation that makes that possible in a browser/WASM runtime, where MySQL is not a practical fit.

A related benefit is support for blueprint.json-style setup files in the playground, which makes it possible to preload modules, themes, users, and configuration in a simple and reproducible way.

This PR is intentionally framed as experimental. The goal is not to replace MySQL/MariaDB for standard production deployments, but to make new execution environments possible for testing, onboarding, demos, and browser-based experimentation.

[Daniel-KM]

Yes, very interesting. Omeka works fine with PostgreSql too, so something more generic to use any sql engine would be very useful.
Furthermore, i was thinking about a way to share config between installs, so why not blueprint.json. Anything that make omeka simpler to manage is welcomed. I published a pr #2432 to use composer to install omeka, while keeping process compatible with the current by-module way.