Fix angular icon mapper

Purpose

Fixes icons for non-angular files that only contain the component part.

1. component.ts → TypeScript
2. foo.component.ts → Angular Component

getIconForFile will accept the full file name.

We match 4 types of filenames:

1. Full match: something like angular-cli.json ← Angular config, not a regular JSON file
2. 3 level deep match: <something-here>.sln.dotsettings.user
3. 2 level deep match: <something-here>.component.ts ← produces Angular component, not a TS file
4. Base file extension: component.ts ← produces TS file, not an Angular component

Fixes gitlab#478102 (closed).