This PR introduces separate `package.browser.json` file for `*-browser`
npm packages (`@tursodatabase/sync-browser` and
`@tursodatabase/database-browser`).
The packages are nearly identical and the only change is `package.json`
content (browser package mentions only WASM optional dependency which
shouldn't confuse NPM and force it to download WASM dep package instead
of native one).
Due to that, innocent "hack" is implemented which swap `package.json`
with `package.browser.json` before publish of `browser` package.
Closes#2906
