Update county related endpoints

[aniri]

Some updates are needed to the CRUD endpoints for counties.

The current endpoints are:

Needed updates:

• the post county endpoint should only be used for adding new counties and not for editing existing counties. It should not need an id.
• a put by id endpoint for editing counties (this logic is probably now handled in the post endpoint)
• a delete county by id endpoint

[idormenco]

will do