Make sure proposal validations do not break install

This references PR #894 and BNC #860117
Do not run validations from within the apply_role
Skip after_save validation on creating proposals

And add comment explaining why
Merge pull request #938 from bkutil/fix/proposal_validations

Fix/proposal validations
Fix i18n parameter key in SupportController error
Add regression test for i18n key fix
Merge pull request #949 from bkutil/fix/i18n_param_fix

Fix/i18n param fix
Use correct font size for list of nodes for roles
Fix tests for proposal validations
Merge pull request #954 from vuntz/fix-font-size

Use correct font size for list of nodes for roles
Merge pull request #953 from bkutil/fix/test_fix_for_proposal_validations

Fix tests for proposal validations