fixes #2685 incorrect and inefficient regexp checking medium name format

It takes eternity to compute something like this:

"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa b" =~ /\A(\S+\s?)+\Z

Also "this is wrong " was not matched
(cherry picked from commit cd2892774b6f6073bb189bd17ea7fcaec76388e6)

fixes #2660 - settings, improve tests and fixes

- added string settings type
- fixed tests previously commented out due to CI failures
- more tests for core settings functionality
- parsing of string values enhanced and extracted to a separate method
- setting value to nil when it equals default is back...

fixes #2334 - location matcher doesn't match on smart parameters
(cherry picked from commit c7f527779d80e1cc78e1f3b02a6ba7bfc081a95d)

fixes #2631 - fix remote code execution via controller name (CVE-2013-2121)
(cherry picked from commit ef4b97d177c58c9532730d53dca0517bc869a0ce)

Conflicts:
app/views/common/_puppetclasses_or_envs_changed.html.erb

fixes #2630 - restrict assignment of roles to those a user has (CVE-2013-2113)
(cherry picked from commit bae665de387d63f93740670ec2542db90084d0eb)

fixes #2386 - permission failure on create_lookup_value
(cherry picked from commit 6c492cce87e0f2ec6c9f4a15115f4394ce542979)

Fixes #2615 - failed to save host group

If there was current organization selected, organizations got doubled
which prevented save. Fixed and added test for this part.
(cherry picked from commit 410505f49b09e8b9295551e5b2ff9f7fe95add6e)

fixes #2285 - subnet validation - length of addresses, strip whitespace and fix common typos
(cherry picked from commit 31aa5db511a6decf800e68a2b6f6eb3dbf0ae29c)

Fixes #2571 - Deleted admin is recreated
(cherry picked from commit 4df2e17b75c65fa657ef9499ccf9c71547f11dcf)

Fixes #2502 - session expiration updates

Signo now allows to transparently prolong user session which got
expired. Also when you now logout from Foreman you will end up in Signo
login form. This brings some code clean up and test changes and small
SSO method API change....