#29 introduce custom page dto, add @RequestMapping to PlantsController to simplify mappings on controller methods

#27 seeding data now fixed, command line runner moved to config class to clean up the main application class

update: WishList #7: check for user before changing wishlist and filter for plants which can be planted in the current week and added requests to requests.http

#3 tests for controller done. @AuthenticationPrincipal is not! injected into controller methods as i could not get it to work. but thats not significant when testing just the web layer. might be a problem when doing full integration tests

#3 fix UserDetailsService bean for tests (rename method to avoid naming conflict, add 2 users & 1 admin). starting tests for GardenController. Added 1 dependency: spring-security-test to mock users in tests

application properties now differ for test suite vs regular runs. persisting h2 database in a file for regular use.