Considerable wasm/js build cleanups and reworking. Remove wasmfs builds from the...

Considerable wasm/js build cleanups and reworking. Remove wasmfs builds from the end-user deliverables and disable the wasmfs build by default, per /chat discussion, as it doubles our deliverable count for only marginal gain. Attempt to move the sqlite3.js/wasm files into subdirectories but rediscovered that that breaks loading in Worker mode because URI resolution of the wasm files differs depending on whether the main script is loaded from a script tag or a Worker.

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