Deprecated davidSDK or update its documentation & add to CI

[SunBlack]

The company behind davidSDK was acquired by HP some years ago. The documentation of PCL still references the old webpage. With some redirects you will see this page. As you can see most downloads are old and the related library seems really inactive (last commit is nearly two years old).

So we have two options:

1. Include the SDK in our CI and update documentation
2. Drop support

In general, I think it's better to remove the support because it won't be developed much more and in case someone still needs it, the person can realize the connection in their own project.