Better named release asserts

[dclong]

Is your feature request related to a problem? Please describe.
The naming of release asserts is confusing. For example, it's not obvious whether gitui-linux-musl.tar.gz, gitui-mac.tar.gz and gitui-win.tar.gz are for x86_64 or arm64.

Describe the solution you'd like
Follow a strict naming convention, e.g., gitui-os-arch.tar.gz. For Linux OS, musl, gnu or unknown can be included.

Additional context
Apps might want to download gitui automatically depending on OS and Arch. A strict naming make this much easier to do.

[extrawurst]

Good point, feel free to create a PR

[magical-heyrovsky]

For everyone else confused by this, the "musl" (what even is this?) binary is apparently for x86_64/amd64.

[stale]

This issue has been automatically marked as stale because it has not had any activity half a year. It will be closed in 14 days if no further activity occurs. Thank you for your contributions.

[extrawurst]

superceded by #2148