Login and registration UI & JWT logic finished (frontend).

See merge request !29

# Conflicts:
#	growbros-frontend/package-lock.json
#	growbros-frontend/package.json
#	growbros-frontend/src/App.tsx
#	growbros-frontend/src/components/PlantDetails.tsx

Closes #40 : Custom useGrowbrosFetcher hook to make calls to the backend.

Closes #40

See merge request !28

#40 custom fetcher hook. clean up base url in backend connector. set up environment variable for backend URL. env interface.

#40 Search plants endpoint: now accepts query params. introduce CustomPage schema on frontend. tests for plants controller done

Resolve "plants controller: GET für einzelne Pflanze"

Closes #41

See merge request !26

# Conflicts:
#	requests.http
#	src/main/java/hdm/mi/growbros/controllers/AuthenticationController.java
#	src/main/java/hdm/mi/growbros/security/ApplicationConfig.java