SSH/TTY console add-on and bug fixes

This is an alpha release for testing. Stability not guaranteed.

Added a SSH/TTY console menu system. Launch it by running postmerkos-console after switch startup (TTY). Still need to reconfigure SSH to allow password mode instead of shared key, as you can't SSH without the shared key presently (connection is refused).

https://www.mediafire.com/file/hm3vmvoopa5ry03/ms42p-postmerkos-webui-20260616-065847.bin.zip/file

This is the nearing the minimum viable product for this firmware. All main features are now implemented in at least an initial usable state. All expected remaining updates for this will be bug fixes and fleshing out how certain aspects of the UI function (both CLI and Web UI). Firmware updater is mature now, but likely could use an extra signal to notify when the update is about to be applied so the disconnection is more clear. I might add an extra function to save update logs to a location on JFFS2 post-flash so the updater can provide final success/fail feedback and logging availability after reboot.

Please provide any suggestions as issues to this repo. To my knowledge, all main issues from Hal Martin's main repo have been fixed and are at initial implementation stage at minimum now.