2 minor syntax fixes in the certificate forms.
Use "CN" correctly as dns or as real name.
Extract EKU-OIDs to class constants.
Guess the profile based on requested eku.
Pre-guess signature for cert based on csr signature.
Adding testcases for gui-domain add.
Add tests for certificate data pre-fillin:

- message digests: sha256/384/512
- cn is dns und cn is real name
- mail/ssl-client/ssl-server EKU
- SANs with dns, mail
- SANs where email from dn is already included.