Add memorymap support to RP2 port

[eightycc]

Resolves #8334 by adding memorymap support to the RP2 port. Also makes these additional changes:

• Changed memorymap hal function prototypes to use size_t rather than uint32_t arguments, allowing prototypes to work with different port word sizes.
• Changes memorymap.AddressRange() start argument from signed to an unsigned int to allow ranges to be specified anywhere in the entire port address map. Added support to the runtime for unsigned int arguments.
• Added wrap-around checking for memorymap.AddressRange() arguments.
• Tweaked Python commentary embedded in memorymap to reflect reality of single operation accesses.

[eightycc]

CI found some breakage. I entirely missed the fact that there are multiple runtimes to consider when adding unsigned integer argument support. Also missed updating the nrf port with the uint32_t -> size_t change. Working...

[eightycc]

@tannewt over to you for review. Thanks!

[eightycc]

After tuning in to the meeting today my understanding of 8.2.x vs. main branch has improved. @tannewt would you like me to rework this pull request for 8.2.x?

[tannewt]

After tuning in to the meeting today my understanding of 8.2.x vs. main branch has improved. @tannewt would you like me to rework this pull request for 8.2.x?

Only if you want to see it in an 8.x release. Otherwise it's fine on main.

[tannewt]

Thanks for the PR! Just a couple questions/suggestions.

[eightycc]

On second thought, let's leave this on main branch.

[tannewt]

Two more minor things. Thanks for the updates!

[tannewt]

Looks good! Thank you!