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
@demobox I see your line of thought, but that would break my current setup at my customer. Any thoughts on how to migrate existing usage which uses to the wls prefix to a new prefix. Of course if labs were to decide to include this plugin in the standard wls plugin we would have to migrate again.