• adding test cases for migrating MDs from ACMEv1 to ACMEv2
• adding test case for checks that missing "acme-tls/1" protocol config is detected
• removing version number for local ACME account storage again (added in v1.99.0). An account
  is only suitable for an ACME server if it matches the directory url exactly.
• export symbols in the module are restricted to reduce size a bit