WIP: Reopen `addrepowindow` prefilled when adding repo fails

[shivansh02]

Description

The addRepoWindow now opens prefilled with RepoUrl, name and extraBorgArguments if adding repo fails. Does not save password due to security reasons, and Encryption because last saved value might no longer be supported on next run of vorta (in case user changes Borg version).

Related Issue

Resolves #1757

Motivation and Context

Add Repo Window does not retain last inputs when adding the repo fails and needs to be filled again.

How Has This Been Tested?

Tested locally by making process_result method of BorgInitJob raise an error intentionally, to mimic failure in adding repo.

Screenshots (if appropriate):

Adding new Repo (which fails): AddRepoWindow opens prefilled next time:

Types of changes

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

Checklist:

• [x] I have read the CONTRIBUTING guide.
• [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 added tests to cover my changes.
• [x] All new and existing tests passed.

I provide my contribution under the terms of the license of this repository and I affirm the Developer Certificate of Origin.