Tea brewing timer

supports green tea timing
contains 6 steps/stages of brewing
- first 30 sec (prepare tea)
- 3 min
- 3 min 30 sec
- 4 min
- 4 min 30 sec
- 5 min

TODO:

Configuration (hard codded version)
- periods configuration
  - list or periods (at least one should be)
  - minutes for each period

Plans

keep statistics
page to show statistics
Add Jest unit tests
Update caching key to avoid old functionality