Checkmk Werk 11933: Rename Versioning variables in agent plugins

ID: 11933 Title: Rename Versioning variables in agent plugins Component: agents Level: 1 Class: Bug fix Version: 2.1.0i1 Versioning variables used to be called: *VERSION* Now they are called: *CMK_VERSION* The only exception to that are Python plugins the versioning variable is still called: __version__