[#IP-215] Add AzureAllowBodyPayloadMiddleware

[balanza]

Add a middleware that allow a specific payload to be provided only by a specific set of user groups.

It is designed for when it's needed to allow only a subset of users to provide a payload that matches a specific subset of the payload schema.

The use case is: we want restrict the opportunity to send a specific field into a Message content to a limited group of users.

[pagopa-github-bot]

	Warnings
⚠️	Please include a Pivotal story at the beginning of the PR title (see below).

Example of PR titles that include pivotal stories:

• single story: [#123456] my PR title
• multiple stories: [#123456,#123457,#123458] my PR title

Generated by 🚫 dangerJS against f3b1ec3

[michaeldisaro]

Just a question: Should this middleware be always combined with the authorization middleware to check that the calling user is effectively into the desired group?

[gquadrati]

LGTM except the test name and what @michaeldisaro pointed out

[michaeldisaro]

LGTM

[balanza]

Just a question: Should this middleware be always combined with the authorization middleware to check that the calling user is effectively into the desired group?

I actually copied that part :

NonEmptyString.decode(request.header("x-user-groups"))

In the end, it's nothing more than a plain text header