Move project creation to a separate page instead of having it on the project list page (for clarity and consistency with the user management)

• manage_proj_create_page.php: new page that prompts for project info when
  creating a new project

• manage_proj_page.php: remove project creation code and replace it with a
  link to manage_proj_create_page.php

git-svn-id: http://mantisbt.svn.sourceforge.net/svnroot/mantisbt/trunk@1812 <a class="text" href="/?p=mantisbt.git;a=object;h=f5dc347c">f5dc347c</a>-c33d-0410-90a0-b07cc1902cb9