Remaining New project link for users that can't create one
### Summary
There are some remaining "New Project" links being displayed to users that don't have any project creation rights.
The creation process then fails as it should with "invalid namespace".
We previously removed most of these links, see #256 and #361 for background.
### Steps to reproduce
1. Create an "external user"
2. Impersonate the user
3. Go to the user profile (should be `/username` URI)
Behold, there's a new project green link as attached.
### What is the current *bug* behavior?
A "New project" link get displayed where arguably it should not, the creation process then fails with an obscure error.
### What is the expected *correct* behavior?
Even if there is a link to the "New project" page displayed to users that don't have creation rights, it should not lead to an obscure error.
#### Details about the Heptapod instance where the bug occurs
Happens on foss.h.n, probably generic.
issue