MBS-6622: Make sure all login pages submit over HTTPS

If SSL_REDIRECTS_ENABLED is true, the action of the login form will be
a https:// uri. If it is not true, then http:// will be used.
MBS-6622: Redirect over SSL when a page tries to display login forms

When a page requires a user to be logged in, it would normally
display the login form. Now, the action first ensures that the
user is connected over SSL before displaying the form. If they are
not, it redirects them to the same page over SSL.
MBS-6622: Don't use return_to_http any more

We now only upgrade the connection to HTTPS and don't worry about
redirecting the user back to a HTTP connection. This fixes the
redirection loop that the parent commit introduced.
MBS-4788: Disable all release group type fields when using existing release group

If the user has selected a release group in the release editor, they should be
unable to also edit the type of the release group (primary or secondary). The
code that was previously responsible for this was not updated for multiple
release group types, so I have updated it to now (correctly) consider the
primary release group type, but also all secondary release group types.
Merge branch 'mbs-6622' into beta
Merge branch 'mbs-4788' into beta