make checkbox for the one repository where codecheck.yml is located

[dxL1nus]

• all repositories should have a radio checkbox to select where the codecheck.yml is located
• if the checkbox is checked, all other checkboxes should be uncheckable and the Load Metadata Button should only appear for this repository
• if the repository has the 'codecheck.yml', this should be saved in the OJS database as well

[dxL1nus]

Selecting the Repository with the 'codecheck.yml' now works in the Frontend and it is saved in the CODECHECK metadata DB table.

---

In the CODECHECK metadata DB table repositories are now stored as follows:

metadata.repository = {
    repositories: 'https://test.com, http://github.com/some/test-repo',
    repoWithCodecheckYaml: 1,
}

Therefore metadata.repository.repoWithCodecheckYaml is null if Contains 'codecheck.yml' file was selected for none of the repositories.