os-udpbroadcastrelay: Expose new configuration flags

[jintakhan]

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• [x] I have read the contributing guide lines at https://github.com/opnsense/plugins/blob/master/CONTRIBUTING.md
• [x] I have searched the existing issues, open and closed, and I'm convinced that mine is new.
• [x] 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. In addition to the lack of the --msearch option mentioned in #4108, the plugin also lacks the ability to set --blockid, --blockcidr and --allowcidr.

Describe the solution you'd like

• OptionField for configuring the flag --msearch
• TextField for the optional search-term field for --msearch
• IntegerField for configuring the flag --blockid
• TextField for configuring the flags --blockcidr and --allowcidr

Describe alternatives you've considered

• The old method of setting --msearch dial by specifying 1.1.1.3 as the source was deprecated years ago, according to upstream documentation. This leaves the OPNsense plugin in its current state with no way to set this functionality.

Additional context

• These flags were committed upstream more than 3 years ago. The executable bundled with the plugin supports them no problem.
• --msearch especially would be immensely helpful to have exposed in GUI as it is used to pair the YouTube application on smart TVs to mobile devices.

[bensmithurst]

#4169 implements some of this (thanks to @ZephireNZ). I would love to see some movement on that PR - if anything needs updating I'm happy to have a look at fixing it up when I have time.