Handle models which contain extension annotations with 'old' classnames

In 8.0 some classes were refactored, eg
com.metamatrix.metamodels.relational.impl.BaseTableImpl - changed to -
org.teiid.designer.metamodels.relational.impl.BaseTableImpl

Need to account for 'legacy' models which may contain extension annotations with the 'old' com.metamatrix classnames. These annotations need to be detected and reset to the 'new' org.teiid.designer classnames.