Change the way Designer's server framework interprets VDB status to replace Active/Inactive with isValid() check as Status value

1) Set-up simple JDBC source/model/vdb and test/execute VDB
2) Delete the Data Source in the Server view
3) Try and execute the VDB again and get exception logged in console

Seems the active/inactive status is old terminology and Designer should be using the isActive() call as well as getValidityErrors() to fine-tune the state of a VDB and prevent Execute VDB from being launched or at least a warning message check.