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
Restarting SSL channels is a very low cost operation and can be executed after the deployment step (40). 90 is on the safe side. I'm not sure if we would ever want to change this.