Make sure proposal validations do not break install

This references PR #894 and BNC #860117
Merge pull request #940 from tboerger/release/roxy/master

Added some missing commands to devguid documentation
Do not run validations from within the apply_role
Restructured and fixed gem versions for iso build again
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
Added environment check to rake tasks
Removed chef dependency from rails
Added additional css classes to various html elements
Merge pull request #956 from tboerger/feature/additional-classes

Added additional css classes to various html elements
Merge pull request #944 from tboerger/feature/gem-fix

Restructured and fixed gem versions for iso build again
Fixed switch name if it is available
A new validation check:

* validate_count_as_odd_for_role
  As the name describes we want to check that we have an odd number
  of nodes used in a role.

Signed-off-by: JuanJose 'JJ' Galvez <jj.galvez@inktank.com>