feat: News Service

[sansan88]

The news page has 3 sources (services) to get News Data based on different configurations.

• team (0:n)
• club (1:n)
• association (0:n)

News Page file:
https://github.com/myclubapp/app/blob/feat/2022/src/app/pages/news/news/news.page.ts

current state:

• each news type is called within a separated method. (generally okay, but could be done better to avoid duplicate entries).
• a loading spinner is shown while loading data.
• news entries can be duplicated when updated. (This needs improovment)
• based on the userdata (Auth Service > GetUser) the list of clubs and the list of teams can be found. (this is OK)

Todo:
these three service calls can be combined with the help of rxjs functions. Important is, that news entries don't get duplicated when edited in the database.