Remove old xknx dependency

Still relying on the old TravelCalculator method from 0.9.4 - which works well here.
To avoid xknx version conflicts, as per @farmio suggestion dependency is removed by copying these functions to the component.

Availability template added

Update README.md

Update hacs.json

Update README.md

Update manifest.json

Update manifest.json

Merge pull request #21 from barmazu/knx_0_17_1_integration

integrate with latest xknx version - reverted cover directions

Update manifest.json

Fix wrong knx version.

Update manifest.json