Add support for Waveshare 1.54" ePaper
This is a minimal invasive version of @dAjaY85's ePaper integration with a few fixes. Until this has been merged it should be way easier to rebase it without the merge conflicts due to the renaming of the DisplayClass.
I hope that the pull request will be integrated into the master branch.
I would like to switch to OpenDTU, but I am already using the ePaper Display with AhoyDTU. I don't really want to buy a new display :)
I've updated the PR to master & fixed the issue with the display not updating the last timestamp.
@mtavenrath could you also check if there is still something missing regarding the merge of #2306 this week ?