Consider updating Angular configuration to match file patterns automatically

[jattasNI]

In research for #126 we noticed that our JS and TS rulesets can automatically target *.js and *.ts files but the Angular one requires client repos to specify overrides for *.js, *.ts, and *.html in their eslintrc. We should evaluate whether the Angular ruleset can and should behave like the others. (Counterargument: when exploring other styleguides, we saw examples where they provided configs that didn't specify file patterns to match).

If we decide to do this, it should include updating the docs for the Angular config to remove the need to specify overrides.

[rajsite]

In triaging this seems like a systemlink convention, @rajsite will double check and close issue / update systemlink docs