feat: implement PUT for inventory UPF

[patriciareinoso]

Description

This PR implements the edition of UPFs

• Create an index over hostname for UPFs to guarantee unique hostnames in DB
• Modify POST operation to remove the target from path: now hostname and port are specified in the body of the request.
• We cannot create 2 UPFs with the same hostname.
• Add PUT operation:
  • If the UPF hostname does not exist it is created.
  • If the UPF hostname exists, it is modified.
• Add validation over PORT

Given that we can create a NS containing a UPF before or after the creation of a UPF object, the PUT and the POST UPF operations are propagated to the NS containing it.

Edition of UPF is propagated to Network slices containing a UPF with the given name using a PATCH operation to modify only the UPF field.

We use transactions to ensure that both DB updates are successfully executed or reverted.

The POST and PUT handlers do not use the config channel -> reduce complexity.

[gatici]

Looks good. A minor comments are added.