- added Error Handling for missing env Variables

Closes #6

See merge request swp-ws21-fahrtenbuch/team-einhorn/fahrtenbuch!6

dockerize application

See merge request swp-ws21-fahrtenbuch/team-einhorn/fahrtenbuch!4

- Split server and client into two separate packages.
- Update README with info on how to start dev server locally
- Client
	- Update react-router-dom to v6
	- Separate page components from UI components
	- Add "proxy" field to package.json for proxying api requests to the backend server
- Server
	- Update path of static file serving to new client directory
	- Update scripts

Implement pipeline

See merge request swp-ws21-fahrtenbuch/team-einhorn/fahrtenbuch!2

convert react class components to functional components

Closes #1

See merge request swp-ws21-fahrtenbuch/team-einhorn/fahrtenbuch!1