[feat] Read from html-validate config file

[abose]

Describe the problem

we already do this if the config is in project root by manually reading the config file, evaluate if the current impl does the job or a more native solution is needed. Search for configPresent metrics to see if anyone is using custom html validate config file and we we have a lot of uses, consider next steps on the issue.

html-validate projects can specify a custom config file. this was earlier not done as the support for vfs was not there, now it seems that the feature is added.

Describe the solution you'd like

https://gitlab.com/html-validate/html-validate/-/issues/213

One would need to implement a custom ConfigLoader which can read the configuration from the virtual filesystem (not sure what vscode calls it) and a custom Resolver which can load files from the very same filesystem.

Alternatives considered

No response

Additional context

No response