[REQ] support matrix parameters and other parameter styles in typescript-angular

Created by: HonoluluHenk

Is your feature request related to a problem? Please describe.

I need to access a server that is making heavy use of matrix parameters (i.e.: "in": "path", "style": "matrix"). At least the "typescript-angular" generator does not support any other parameter-styles than simple.

The way parameter encoding currently is implemented, modifying the mustache-templates does not work: AbstractTypeScriptClientCodegen.java generates some hardcoded Typescript code that is broken for other styles than "simple".

Other typescript-* generators are probably "broken" in the same way since they make use of the same Java abstract generator class, see above.

Describe the solution you'd like

I'd like to have either a) have correct code generated for all supported parameter styles (at least "style": "matrix") or b) have code generated in a way that allows for customization via mustache-templates.

Describe alternatives you've considered

I tried to customize api.service.mustache but the relevant/wrong code is hardcoded in AbstractTypeScriptClientCodegen.java.

Additional context

n/a/