Remove Phproject (Unmaintained since May 2023, demo down)

- ref: awesome-selfhosted#1
- `ERROR:awesome_lint.py: Phproject: last updated -367 days, 1:30:35.270761 ago, older than 365 days`
- [Demo has been reported](Alanaktion/phproject#415) down since November 2023 with no signs of life
- [A fix which was done due to a Error 500 in March 2023](Alanaktion/phproject#406) was merged into the main branch, but not released (ref: [Internal Server Error](Alanaktion/phproject#417))