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
I think it should, but we should fix this in the WLS plugin (wls/runtime/base.py). The only reason I needed to include this here was to also support restarting the SSL channels of an OSB Server (so we should also add this method to base.py of the OSB plugin).