Fixes #12834 - Avoid select2 integration test deadlock

The test was testing that selecting a hostgroup (1), then clicking on
inherit environment, then selecting another hostgroup (2) should return the
original environment. That overrides hostgroup 2 environment.

Fixes #12793 - reverted field filtration to enabled fields only

Fixes #12794 - Defined logic when properties should be sent to server

If hostgroup is not set - always send the parameters.
On hostgroup change - remove inherited parameters from the request, so the values from the hostgroup will take place.
On save - send the values according to the state of the "inherit" button.

Fixes #12828 - Hidden value checkbox enabled after override button is checked

Fixes #12659 - Fixed "inherit" behavior

Non-inherited attributes are now sent in the form data.

Fixes #12752 - Host and hostgroup clone should copy smart class parameters overrides

Fixes #6007 - Allowing to hide smart class parameters

Fixes #12642 - Show overriden values before type cast on host edit form

Fixes #12506 - Show smart proxies version in about page

Fixes #12609 - correctly display boolean parameters on host edit form

Booleans were not displayed correctly in certain cases due to the fact
that `false.present? false` and `lookup_value.value ||
inherited_value true` in case one of them is true.