Build separation for ARP/ND

[HTRamsey]

Improve Build separation for IPv4/IPv6

Description

Only include FreeRTOS_ARP if IPv4 is enabled. Move everything else into routing which calls either ARP or ND. Also create a frame agnostic helper for checking the cache.

Test Steps

Need to finish adjusting a couple tests

Checklist:

• [ ] I have tested my changes. No regression in existing tests.
• [ ] I have modified and/or added unit-tests to cover the code changes in this Pull Request.

Related Issue

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[paulbartell]

Thanks for the PR. Looks like there are a few formatting and other CI checks that need to be addressed. I'll make sure to send this to the team for review as well.

[paulbartell]

/bot run formatting

[HTRamsey]

@tony-josi-aws I noticed some issues with ARP/ND in this and I started to fix them but didn't want to lose focus of the point of this PR. I'll make a separate PR for that.

[HTRamsey]

@tony-josi-aws Also parts of xCheckRequiresResolution and xStartAddressResolution are currently redundant so I need to reconcile duplicate functionality as well. I'll save any functionality changes for a different PR so that this mostly just helps build separation. The other issues I mentioned are things like unsolicited solicitations not working as expected, as FreeRTOS_OutputAdvertiseIPv6 is called in the gratuitous arp code which is triggered in DHCPv4. Also it always sets the ndICMPv6_FLAG_SOLICITED flag. vARPAgeCache and sending gratuitous arps need to be decoupled as well.

[HTRamsey]

/bot run formatting

[HTRamsey]

/bot run formatting

[HTRamsey]

@tony-josi-aws I went back one more time to make it simpler and less to review

[HTRamsey]

/bot run formatting