GHA CI: Use preinstalled vcpkg

[Chocobo1]

This will save maintenance work on the vcpkg version.

Also a few other improvements:

• Add quotes to path
• Sort command flags
• Avoid switching shell, always use powershell (the default shell)

[glassez]

@Chocobo1
It seemed to me that you were against it: #15342 (comment)

[Chocobo1]

It seemed to me that you were against it: #15342 (comment)

That was my outdated opinion. Later I discovered doNotUpdateVcpkg: true and done some testing, it seems the suggestion was actually viable (and the caching will still work as expected).

[xavier2k6]

There doesn't seem to be a need for this line at all below:

https://github.com/qbittorrent/qBittorrent/blob/ea5c23224c18dc9fe0ec97c65438ef88eb6dd1ad/.github/workflows/ci_windows.yaml#L23

Looking at logs:
It finds & uses the default commit in CI image as per https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md#package-management

tool: C:\Program Files\Git\bin\git.exe
Fetching the Git commit id at 'C:\vcpkg' ...
6bc4362fb49e53f1fff7f51e4e27e1946755ecc6
vcpkg identified at commitId='6bc4362fb49e53f1fff7f51e4e27e1946755ecc6', adding it to the cache's key.

[Chocobo1]

There doesn't seem to be a need for this line at all below:

https://github.com/qbittorrent/qBittorrent/blob/ea5c23224c18dc9fe0ec97c65438ef88eb6dd1ad/.github/workflows/ci_windows.yaml#L23

Removed, thanks.

[xavier2k6]

Would it also be advisable for consistency & less maintenance to use "latest" label for CI Images across all CI's?
https://github.com/actions/virtual-environments#available-environments

[Chocobo1]

Would it also be advisable for consistency & less maintenance to use "latest" label for CI Images across all CI's?

No, IIRC at least on ubuntu, package names might change for different releases.

As for windows and macos you can submit a PR and discuss it, I'm not so eager to make such changes myself.