[CHORE] remove pph-rphoto command

[mystique09]

Description

Unsplash now requires user to register as developer to get access to their gallery.

Fixes #238

Type of change

Please delete options that are not relevant.

• [x] This change requires a documentation update

How Has This Been Tested?

Manually

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

Test Configuration:

• Firmware version:
• Hardware:
• Toolchain:
• SDK:

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] My changes generate no new warnings