#29 removed tmd specific code out of Security folder; reverted Security code...

#29 (closed) removed tmd specific code out of Security folder; reverted Security code as much as possible to API demo state

In this ticket the code in Security folder is reverted back to the state of API Demo as much as possible and TMD functionalities are kept. Some classes are added, and the differences exists still in classes OidcProvider, EntityUtils, SerialisationGroupsHelper, but those changes are not breaking other use cases.

As a next step it would be good to create composer package out of Security folder, include it into TMD, Taxonomy and API Demo. After that additional refactoring can be considered in the package itself.