docs: use nominatim-project everywhere

[mtmail]

Keeping it the same as other documentation and example scripts

grep -rl 'nominatim-planet' .
./docs/admin/Import.md
grep -rl 'nominatim-project' .
./vagrant/Install-on-Ubuntu-20.sh
./vagrant/Install-on-Ubuntu-22.sh
./docs/admin/Deployment-PHP.md
./docs/admin/Deployment-Python.md
./README.md
./.github/workflows/ci-tests.yml
./VAGRANT.md

[mtmail]

CI errors are unrelated

E AttributeError: 'FixtureDef' object has no attribute 'unittest'

[lonvia]

CI should be fixed. Can you rebase quickly?

[mtmail]

@lonvia It's rebased now