Build and deploy DuckDB-Wasm extensions

[carlopi]

NOTE: Last commit has to be reverted, moving to main once duckdb/duckdb#9356 is merged

Build step is tested, signing step is tested (but for verifying the binaries are actually valid, need to add that), deploy step untested.

DuckDB side PR has been merged, bumped to main the workflow.

[carlopi]

I did ended up testing also the deploy, once it's green here it should be good to go.

Right now, on the live shell.duckdb.org:

duckdb> SET custom_extension_repository='https://nightly-extensions.duckdb.org';
duckdb> LOAD quark;
duckdb> SELECT quark('XXX');
┌──────────────┐
│ quark('XXX') │
╞══════════════╡
│ Quark XXX 🐥  │
└──────────────┘
Elapsed: 28 ms

duckdb> 

[samansmink]

Hey @carlopi looks good! very excited to have this working. I added two small comments!

[samansmink]

Good stuff!