refactor(tauri): support for building without environmental variables

[chippers]

Both embedded-server and no-server fully work. Heres a checklist ill keep updated i guess:

• Compressed embedded assets (brotli gzip)
• no-server
• embedded-server
• Pass test suite
• Create additional tests for changed/new code (not really sure what to add for config testing)
• TAURI_INLINED_ASSETS support
• TAURI_CONFIG support
• Refactor AppConfig -> AppContext to prevent repetition. (i.e. &application.config.config -> &application.ctx.config)
• handle public paths as in webpack instead of iteratively removing parents from assets

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This is the replacement for #830. That PR was more about seeing if it was possible, this PR is about actually removing core environmental build variables from tauri.

This branch/pull request should be tracking changes from dev to prevent having a massive conflict at the end. This touches a few "core" files like runner.rs and has some tentacles in otherwise not related code due to moving tauri-api::config into tauri-config so conflicts are definitely going to happen.

As of the first commit, it can build a no-server application that has been run with tauri dev or tauri build to generate the index.tauri.html.

As a high level overview of additional changes planned in this branch:

1. All tests need to be updated
2. Support for embedded-server. (and every existing way of using tauri)
3. Handle additional env vars like TAURI_CONFIG and TAURI_INLINED_ASSETS which are currently ignored

See comments on #830 for a more specific overview if needed

[chippers]

the last commit added support for embedded-server,

Because of some necessary changes to codegen, I lifted the code from the tauri_includedir_codegen repo into tauri-macros/src/include_dir.rs along with the rework. Since the frontend to that dependency also didn't make much sense, I moved tauri_includedir::Files into tauri-api/src/assets.rs as Assets. This commit doesn't add support for gzip since it was not used anyways. It keeps the structure support for it however, and just needs to be actually implemented in the match in include_dir.rs. I left a few TODO comments that should be handled by the time this PR would be ready

[chippers]

Off the top of my head, some todos:

• replacement for the get() testing in tauri-api/src/config.rs
• finish gzip support in tauri-macros/src/include_dir.rs
• support TAURI_CONFIG environmental variable to override any actual config with the content sent in that env var
• make sure TAURI_INLINED_ASSETS actually works, since the code was ported
• probably add some tests around the AppConfig and some more tests wherever the config or environmental variable was previously used

[chippers]

I've left the bundler and cli completely untouched, only touching tauri, tauri-api, and (new) tauri-macros. There's still a few places env vars are used in the latter, such as endpoint assets handling and runner splashscreens.

note for myself:

tauri/tauri/src/app/runner.rs

Line 292 in d0c41e4

let env_var = envmnt::get_or("TAURI_DIR", "../dist");

[lucasfernog]

We should wait for WRY to land on dev before fixing the conflict issues here.

[lucasfernog]

We'll need to archive tauri-includedir since this change kills it :P

[nothingismagick]

This is flipping awesome, but please don't change the TS style and watch out for overly expressive changelog stuff.

[lucasfernog]

My bad 😂