Add OPFS (Origin Private File System) Support to the Latest Version of duckdb-wasm

[e1arikawa]

Description:

This PR implements OPFS (Origin Private File System) support in the latest version of duckdb-wasm based on PR #1490.
This allows database files to be read and written to the OPFS.

API:
When opening a database file, you can now use the following API:

await db.open({
    path: 'opfs://test.db',
    accessMode: duckdb.DuckDBAccessMode.READ_WRITE,
});
const conn = await db.connect();

Changes:

• Added support for OPFS.
  • Bug Fixes:
    • Resolved issues related to COPY TO functionality.
    • Fixed support for signed S3 URLs.

[carlopi]

This is very very welcome, thanks.

I am in the process of releasing a new version of duckdb-wasm, connected to duckdb 1.1.0.
Once that is out, I will properly review this PR.

[e1arikawa]

@carlopi
Thank you very much for your update and for taking the time to review this PR.
I look forward to your feedback once the release is out.
Please let me know if there's anything I can assist with in the meantime.

[carlopi]

One comment would be if you could have a look at the failing test