Creation necessary due to special adaptions to work with the SIFT-Operator

Added new URL to the server api due to changes in the server set up

- Added comments for better documentation

- Added confirm button to end card capturing
- Added scrollbar to capture log if many cards were captured
- Delete picture after sending them to the server to avoid excessive memory usage
- Get points for each player after card capture and sending it to the main game activity

- Realized with retrofit:
  * added api interface
  * Created POJO-Class to convert JSON Answer
- Connection and sending to server works
- TODO:
  * Wait for server to answer (lab set up takes way too long)
  * Get response and show it to user

- Removed openCV libs
- Issues: Take more than one picture fails
- TODO: Saving the picture not needed, just send it to the server

- Added comments
- Card capture layout

- User can now choose what was announced in an extra "window"
- Choosing activity adapts itself based on the choices made by the user
- After confirming the announcement is shown on the main game layout
- Some comments added for better documentation

- Working start screen
- User can enter the player names
- Main game layout with no functionality included