IBX-5710: Shipping REST API

[MagdalenaZuba]

Question	Answer
JIRA Ticket	https://issues.ibexa.co/browse/IBX-5710
Versions	4.6
Edition	N/A

Added templates to:

• GET /shipments (ibexa/shipping#29)
• GET /shipments/{identifier}
• PATCH /shipments/{identifier}
• GET /shipping/methods (ibexa/shipping#25)
• GET /shipping/methods/{identifier}
• GET /shipping/method-types (ibexa/shipping#24)
• GET /shipping/method-types/{identifier}
• GET /orders/order/{identifier}/shipments (ibexa/shipping#29)

TODO:

• Rebuild rest_api_reference.html one last time before merge

Checklist

• Text renders correctly
• Text has been checked with vale
• Description metadata is up to date
• Redirects cover removed/moved pages
• Code samples are working
• PHP code samples have been fixed with PHP CS fixer
• Added link to this PR in relevant JIRA ticket or code PR

[adamwojs]

@MagdalenaZuba rebase is needed here

[MagdalenaZuba]

@adamwojs this PR is marked as work in progress, I just provided skeleton, Andrew took over on Aug 31 and will provide examples and fill in missing information as well as perform rebase

[adamwojs]

I've converted it to a draft in order to skip going through this PR next time 😉

[adriendupuis]

Probably ready to merge but wait for #2289 which will remove the pollution of unrelated entries.