* Added availability_template to Template Lock platform
* Added to test for invalid values in availability_template
* Black and Lint fix
* black formatting
* Updated AVAILABILITY_TEMPLATE Rendering error
* Moved const to package Const.py
* Fix import order (pylint)
* Moved availability_template rendering to common loop
* Brought contant into line
* Cleaned up const and compare lowercase result to 'true'
* reverted _available back to boolean
* Fixed tests (async, magic values and state checks)