Remove issue-specific links from project page links

It's weird and wrong that project.module is conditionally populating a bunch of issue-specific links to the project links on behalf of project_issue. Really, that should be project_issue.module's problem via hook_project_page_link_alter().

However, now that #425728: Add an "issue cockpit" block for project nodes is done, it seems silly to duplicate all of that inline in the project nodes. I think the block is just much more useful, and folks should be encouraged to use that, instead. The only thing we'd lose is the "View pending patches" link, which is slightly lame due to #27865: Remove hard-coded status options, but at least for now we should probably retain. That should just continue to live under the "Development" section for now.

So, this issue will be for a few inter-related patches:

A) Removing all the project_issue-related cruft from project.inc

B) Adding a hook_project_page_link_alter() implementation to project_issue for the pending patches link.

C) Cleaning up the alter implementation in drupalorg.module based on how things are now setup.

Seems easier to just do it via a single issue than separate, inter-dependent issues in different queues.