..F....... [ZBX-8874] Fix "Add" button in flexible interval "sub"-form intercepting "Enter" keypresses from main form.
- Implement jQuery plugin "enterSubmit" which allows to specify which submit button should be activated when user presses "Enter" key in form input field or select element.
- Update LLD rule edit view, item edit view (used in both normal items and prototypes) and item massupdate view to have class "subform" attached to container element of flexible interval "sub"form.
- Update init.js to run "enterSubmit" on all forms in page and use submit button with class "main" as default submit button.
- Replace SPACE constants with " ".