Remove all OGC related content from teamengine source code

[dstenger]

Background: Other parties than the OGC use the software TEAM Engine as well. Thus, OGC related content should not be found in the source code meaning that, for example, the default web interface does not contain any OGC related links etc.

The content shall be migrated to a different repository instead (e.g. https://github.com/opengeospatial/teamengine-site, https://github.com/opengeospatial/teamengine-docker).

For example, this pull request introduced OGC related content: #424