net/firewall - Add API support for port definitions in firewall plugin

[AdSchellevis]

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• I have read the contributing guide lines at https://github.com/opnsense/plugins/blob/master/CONTRIBUTING.md
• I have searched the existing issues, open and closed, and I'm convinced that mine is new.
• When the request is meant for an existing plugin, I've added its name to the title.

Is your feature request related to a problem? Please describe.
Currently the firewall API does not support the use of aliases, this ticket aims to add this type of validation so port aliases can be used.

Describe the solution you'd like
Accept aliases in a similar way as they are already supported for network fields in the API (no extensive gui, properly validated when supplied).

Describe alternatives you've considered
none

Additional context

plugins/net/firewall/src/opnsense/mvc/app/models/OPNsense/Firewall/Filter.xml

Line 70 in ce6803c

<!-- XXX: known limitation, aliases not supported by PortField -->

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