Add angular language server

[pebrianz]

Following intruction to enable it
Install @angular/language-server with npm

npm i -g @angular/language-server

Install @angular/language-service as dev dependencies in project

npm i -D @angular/language-service

Add angular to language-servers html and typescript in languages.toml

[[language]]
name ="html"
language-servers = ["angular","vscode-html-language-server"]

[[language]]
name = "typescript"
language-servers = ["angular","typescript-language-server"]

Auto completion and error checking

Goto reference and goto definition

Related to #4861