fixing public user documentation

fixing public user documentation
adding login link to the public access doc
formatting new text
Merge remote-tracking branch 'origin/dev_4_4' into rebased/dev_4_4/public_user

Conflicts:
	omero/sysadmins/unix/install-web.txt
Merge pull request #524 from aleksandra-tarkowska/rebased/dev_4_4/public_user

fixing public user documentation (rebased onto dev_4_4)