weblogic-certificate plugin

Initial version of the weblogic-certificate plugin

Introduces 2 new Containers:
- CustomTrustKeyStore
- CustomIdentityKeyStore

and 2 Deployables
- TrustCertificateSpec
- IdentityCertificateSpec

and an SSL Channel restart contributor
that's the whole point, it blocks until the server is in a stable state, currently defined as not SHUTTING DOWN or STARTING, which means it's either SHUTDOWN or RUNNING.

Anyways I think I borrowed the code from the OSB plugin ;-).