Show invalid form warning beside create button on ServerCreate page
Overview
This MR addresses following problem of the ServerCreate page (from #668 (closed)):
The warning on form should not be hidden in a tooltip on create server page. We should just disable the button and show the warning on the space left of it.
In general, displaying client-side errors in the form in line is sufficient. From material design
If you are performing inline form validation, and the field with the error is clearly marked, the submit button may be disabled until the error is corrected.
PF also suggests to do only inline validation for client-side error checking, with showing an optional alert at the form level (containing a generic message to address problems in form fields).
But since we already have code to enlist all input fields' errors together, I used that to create a one-sentence error message instead of showing list of error messages for each field again at the form level. This removes redundancy of error messages at the form level (as we have shown each error message inline already) and also makes design cleaner.
How to Test
Enter invalid inputs in server create page.