ResourceAdapter vs. Serializable

We should add an option to let the ResourceAdapter class implement Serializable.

Resource adapter class name [AcmeResourceAdapter]:
Should the resource adapter class be Serializable (Y/Yes/N/No) [N]:
Resource adapter config properties [enter to quit]:

If the answer is "Y" then let the ResourceAdapter class implement the java.io.Serializable interface and set a serialVersionUID field to 1L.

If the answer is "N" then do

private transient ResourceAdapter ra;

for all objects that implements ResourceAdapterAssociation.