Rework and update the documentation before release 1.0

[Knitschi]

The documentation is not completely worked out right now. This should be finished when all features for the 1.0 Release are done.

We should consider the following:

• Choose a template that is also readable on phones. The "Read-the-Docs" template that is used by conan seemed to work.
• Maybe rework the api doc structure by splitting it into smaller peaces.
• Make sure CPFCMake#27 is implemented.
• Add Boost cmakemodules to the list of similar projects if boost has made the change to CMake before our release.
• Add more details to the similar projects list about what exactly the similarities are.
• Document the compatibility guarantees. -> There are none for now.
• Fill empty pages.
• Re-Iterate over everything to get a consistent style.
• Document the lack of the multi-config feature.
• Acquisition via package manager?