refactor(generate_assets & generate_static_assets)

[symful]

Ignore the other 8 commits. I accidentally messed up a bit. Newbie mistakes at using GitHub.

[symful]

Though files in JavaScript is quite weird. Where do we even specify webkitRelativePath into the File constructor and why does it even exist in first place? Do we need to manually modify it if we need to set the value? Though it is read-only property. But if we try to just using Object.assign + Blob constructor without it, TS will be mad at me because the expected return value type is File.

Sometimes JavaScript is quite verbose regarding objects like this.