feat(registry): replace yq exec in file: source

[baod-rate]

for the file: registry source, replace the call to yq with a vendored pure-lua yaml parser.

This reduces our dependencies on external programs, especially since yq is not easily available on every system. e.g. the default yq program in Arch is kislyuk/yq rather than mikefarah/yq as command seems to expect.

I confirmed by comparing the json output of the github:mason-org/mason-registry source against the json-encoded output of the file: source pointing at a local copy. Other than the order of some fields they are exactly the same

[williamboman]

Thanks for the PR! I'd definitely prefer a no-dependency variant of this. I don't believe I ever tried tinyyaml when initially adding this capability, all other options I tried failed to properly parse simple YAML so I decided to offload it to yq.

I'm unable to find details on exactly what "subset" of YAML this implementation supports. I see you've modified the upstream code to support multi-line strings. Before moving to this implementation I'd like to better understand its limitations to avoid situations where the registry changes in such a way that it no longer is parseable. Do you happen to know what it doesn't support? I tried a couple of YAML documents from different sources and the only issue I discovered so far was multi-document files.

I'd also like to add that the file: protocol is so far only really added to aid in testing registries and is not really meant to be used "permanently".