ci(publish): add initial publish app GH workflow

[h1dden-da3m0n]

Description

This is an initial attempt on offering a replacement for the sol remaining Azure CI workflow.
Any feedback is welcome and the are still at least 2 steps missing from the original workflow (namely: CopyFilesOverSSH, SSH, mostly since I don't know what they are exactly used for or how to replicate them).

Changes

• Add publish GitHub workflow

Issues

• n/a (move from Azure CI to GH Actions)

[nielsvanvelzen]

(Only reviewed until the signing part)

Ideally the publishing workflow also publishes test versions (on the master branch) that are not signed. The Kotlin SDK works similarly. See https://github.com/jellyfin/jellyfin-sdk-kotlin/blob/5d1d7e3600d8f9d2f98dd5dbc2a68f4090f4f416/.github/workflows/sdk-publish.yaml

[h1dden-da3m0n]

okay, I am not 100% on the repo upload script NGL. Please let me know what you think of that, otherwise this should cover the requirements to this workflow.
There are a few secrets that would be required to be added to the repo should the workflow in its current form be accepted, but I expect this to still go throug an iteration or two.

Note I plan to squash the workflow commits in the end unless you want the full history, but this should be discussed at the end.

[h1dden-da3m0n]

okay I opted to remove my shell script in favor of two actions, I found them to be more straight forward (however I can always revert if you like the script more)
There are several secrets that this workflow would require to be added to this repo before it would work and I still need to squash the workflow commits, but functionality wise it should be equivalent to the Azure CI pipeline.

[nielsvanvelzen]

Note: do not merge until secrets are added.

[Maxr1998]

LGTM. Waiting for all secrets to be added before merging.