Redirect (re)signing of CCLA to Contributors tab.

When a user signs or resigns a CCLA, redirect them to the Contributor
invitations tab.
Redirect user to signature list after signing ICLA

After a user has signed an ICLA, redirect them to the list of individual
contributors (currently the Contribute menu nav item). This removes any
confusion dealing with resigning or refilling out the form.
Update non-admin CCLA signature view text.

In the manage profile agreements tab, update the language surrounding viewing
the CCLA signature content. Eventually, this should be changed to view
Organization or view Contributors where the user can view the other members of
that organization instead of the form to update the signature.