Remote Reindex UI improvements

[gally47]

In this PR we:

• [x] improved the indices sort
• [x] added support for hostnames with / at the end
• [x] made sure the form value is saved when we retry to migrate

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Refactoring (non-breaking change)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes.