Update of Credential Store alias operations

Recent updates of Elytron subsystem in WildFly core contains reworked operations on aliases stored inside Credential Store. Older approach with having aliases as resources was not ideal, so from now on we use operations on credential-store resource.
Let me give you some examples:

Create credential store named "test":

 /subsystem=elytron/credential-store=test:add(location=test.storage, relative-to=jboss.server.data.dir, credential-reference={clear-text="secret2"}, create=true)  

Add alias "my_db_password" with secret value "supersecret":

/subsystem=elytron/credential-store=test:add-alias(alias="my_db_password", secret-value="supersecret")

Check presence of aliases:

/subsystem=elytron/credential-store=test:read-aliases()

Change secret value attached to an alias:

/subsystem=elytron/credential-store=test:set-secret(alias="my_db_password", secret-value="notsosecret")

There is a reload operation which can be used in case the storage file was modified by outside process. Credential store "test" has to be reloaded the change can take the effect:

/subsystem=elytron/credential-store=test:reload()

Finally we can demonstrate removal of the alias from credential store "test":

/subsystem=elytron/credential-store=test:remove-alias(alias="my_db_password")