[BUG] Reduce redownloading of unchanged files

[Sarkie]

Describe the bug
Currently the same files are being downloading from gitub

To Reproduce
Start the software
Files will be downloaded

Expected behavior
Github api uses ETag, so you can use If-Match header on the GET request to reduce downloading

Screenshots

Device:

• Device: [e.g. PSP Model or VITA]
• FW:[e.g. Current System Firmware]
• Daedalus Version 0.2 Nightly

Additional context
Add any other context about the problem here.

[Sarkie]

@Rinnegatamante also noticed the comment regarding Content-Length missing, I think there's a bug or something with Github api - I've created a forum post.

https://github.community/t5/GitHub-API-Development-and/Content-Length-missing-randomly/m-p/57784#M4856

[Rinnegatamante]

It's not a bug, GitHub API uses chunked transmission. Chunked transmission misses Content-Length.

[e-minguez]

What about generating MD5 files? So you can check the checksum and download only a few bytes.