Restrict use of templates

[kuehne-trustable-de]

The list of templates available by the ADCSProxy should be enumerated in a whitelist. This feature should prohibit the use of (high value) templates not intended for remote use.

A whitelite is the best option from the security point of view, but it may be annoying in a test setup. So alternatively a blacklist (prepopulated with default templates) should be implemented .