!apps: Simplify NuttX initialization

[linguini1]

Summary

BREAKING:

In an effort to simplify board initialization logic for NuttX, NSH will no longer support architecture initialization. This will happen during boot via the BOARD_LATE_INITIALIZE option. The boardctl command BOARDIOC_INIT is also no longer available from user-space.

Quick fix: Any application relying on BOARDIOC_INIT should now enable BOARD_LATE_INITIALIZE to have initialization performed by the kernel in advance of the application running. If control over initialization is still necessary, BOARDIOC_FINALINIT should be implemented and used. Boards relying on NSH for initialization should also enable BOARD_LATE_INITIALIZE instead.

Part of apache/nuttx#11321.

To be merged with twin PR to NuttX kernel: apache/nuttx#18408

Impact

This reduces the complexity of NuttX initialization by keeping it within the
kernel logic for the normal case. Users can still control initialization from
their application using BOARDIOC_FINALINIT instead.

This impacts almost every NuttX supported board, as many configurations relied
on NSH for initialization. This also impacts each application in the diff which
relied on BOARDIOC_INIT.

Testing

TBD, I will likely need help testing the affected applications (for this PR).

Testing of modified NuttX kernel defconfigs can be found in the twin PR: apache/nuttx#18408

[linguini1]

NOTE: The CI will always fail since it will be using a version of NuttX where the defconfigs still contain references to NSH_ARCHINIT.

[xiaoxiang781216]

why check CONFIG_BOARD_LATE_INITIALIZE

[linguini1]

I suppose my idea here was the use-case raiden mentioned, where users that still want control over the init process put a custom one in board_finalinitialize. But, I guess in that case they should be allowed to enable both options anyways. I will modify this (and anywhere else I did this) to just check for CONFIG_BOARD_FINALINIT.