VS Code Extension: Add github.dev support

[abhi40308]

Component

VSCode Extension

Is your proposal related to a problem?

Currently the web version of Hasura VS Code extension has full feature support on vscode.dev, but not on github.dev.

github.dev allows users to quickly open any github repo in VSCode (in the browser) and make some quick edits. Currently we only support structural (json schema based) validations, autocompletes, snippets and hover documentation on github.dev, but the semantic support is not there.

Describe the solution you'd like

It would be nice to have semantic features support like intelligent (project context based) autocomplete, validations, rename operation, etc on github.dev. i.e. Get 100% feature parity with native extension or vscode.dev, on github.dev as well.