PIN 5554 eservice isDelegable

[MalpenZibo]

Closes PIN-5554

This PR:

• adds the isDelegable flag on the service model
• add the ability to get/create/modify this flag using the existing eservice endpoints

The ability to change this flag on published events will be implemented in this task https://pagopa.atlassian.net/browse/PIN-5700

Manual Test

Create eservice

Update Draft

Get eservice descriptor

Get producer eservice

Get producer eservice descriptor

API GW Get Eservice

[ecamellini]

Some comments about BFF routes where we should add the flag + some other minor things

[ecamellini]

Three things are still missing IMO:

• Adding the flag into the various read calls in BFF and API GW (only the ones that don't return compact data)
• Adding the flag into the eservice import/export in BFF (see fileUtils.ts)
• Updating the corresponding Bruno calls, performing some manual tests, and adding some test screenshots to the PR

You can use #1109 as a reference for all the points, where I did the same for the isSignalHubEnabled flag. I would do these things into the same PR so that it becomes another good reference on how to add a new field into a model in the future

[ecamellini]

🚀