Improvement for errors displayed on Repository Settings
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### Overview
When entering a bad formatted URL on 'Pull from a remote repository' or ' Push to a remote repository' section, an error is displayed at the top of the page and the current section is collapsed.
### Steps to repro
1. Go to repository settings of a project.
2. Expand the 'Pull from a remote repository' section.
3. Set an invalid URL on 'Git repository URL', i.e: _http://192.168.10.1:1op/test.git_
4. The application makes a hard reload, displays an error at the top of the page and collapses the section
### Screenshot

### Proposal
- Submit the form through Ajax rather than the browser's normal submit mechanism, avoiding a hard reload
- Display the error inside the form:

issue