Use mbedTLS instead of OpenSSL

[Faless]

Improve CI, add x86_32, arm32, arm64 and android builds

Original Description!

Build dependencies using cmake.

I was nerd-sniped by the merge of #191 and #199 to try and switch to mbedTLS as the crypto library.

This should make it much easier to get ARM32/ARM64 (#260) builds on both windows and linux (I've confirmed cross-builds for linux arm32/arm64, for windows, see godotengine/webrtc-native#174 ).

I can add the CI bits as a separate commit to this PR if desired.

[akien-mga]

Seems good to me. If anything we're more familiar with mbedTLS and it works well for Godot, so it's a better pick IMO.

As discussed with @Calinou, we'll first make a release with the new OpenSSL PRs merged (and Godot 4.2 baseline), and then merge this PR and make another release.

So there will be a recent release with OpenSSL and Godot 4.2 to compare with in case there are any new issues related to mbedTLS.

[Calinou]

@Faless Can you look into rebasing this PR? The SSL certificate issue is still being run into regularly with 3.2.1, so I'd like to merge this, tag 3.3.0 and hopefully fix the issue once and for all.

[Calinou]

@Faless Out of curiosity, is this ready for review now?

[Faless]

@Calinou , yes, but is based/depends on #330 and #331

[Calinou]

Trying to push to a test repository to GitHub on Linux x86_64 with the CI artifact build using SSH (my key is RSA-4096):

Found a repository at /tmp/4/.git/.
Selected repository path: /tmp/4/.git/.
GitPlugin: Loaded system CA certificates
GitPlugin: Performing push to origin
ERROR: GitPlugin: Could not connect to remote "origin". Are your credentials correct? Try using a PAT token (in case you are using Github) as your password. Error -16: remote rejected authentication: Failed getting response in godot-git-plugin/src/git_plugin.cpp:_push#L536
   at: push_error (core/variant/variant_utility.cpp:1023)

Replacing the CI build with 3.2.1 and using the same configuration:

Found a repository at /tmp/4/.git/.
Selected repository path: /tmp/4/.git/.
GitPlugin: Performing push to origin
Writing Objects: 0% (0/13, 12 bytes done.)
Writing Objects: 69% (9/13, 1001 bytes done.)
Writing Objects: 69% (9/13, 1049577 bytes done.)
Writing Objects: 69% (9/13, 1973350 bytes done.)
Writing Objects: 76% (10/13, 1973352 bytes done.)
remote:
Writing Objects: 100% (13/13, 1974036 bytes done.)
[updated] refs/heads/master
[updated] 130d0e1...6e22abb refs/remotes/origin/master
GitPlugin: Push ended

However, I tried a second time with this CI build (replacing the 3.2.1 build) and it worked:

Found a repository at /tmp/4/.git/.
Selected repository path: /tmp/4/.git/.
GitPlugin: Loaded system CA certificates
GitPlugin: Performing push to y
Writing Objects: 100% (0/0, 12 bytes done.)
remote:
Writing Objects: 100% (0/0, 32 bytes done.)
[updated] refs/heads/master
[updated] 6e22abb...6e22abb refs/remotes/y/master
GitPlugin: Push ended

Not sure what's going on, maybe I entered the passphrase incorrectly on the first try.