Add support for linking to Trac instances using multiple repositories

[ghost]

When using multiple repositories in a single Trac instance, the name of the repository must be included in the link. The AppendedToBrowser property wasn't sufficient, as the repository name appears in different parts of the link, depending on its context ("changeset:" vs. "browser:" links).

This change modifies the TracProjectProperty class constructor to take another argument (the Trac repository name). It also adds wraps the config.jelly elements in a "section" element, which seems to fix the "advanced" section not showing up (Jenkins 1.609.1) on the configuration page.

[jenkinsadmin]

Thank you for a pull request! Please check this document for how the Jenkins project handles pull requests

[TafThorne]

This looks like a helpful enhancement to match the trac multiple repositories facility. I will try and get this updated code working on my Trac instance (which has 3 repos in it) and then feed back here. I can start following the suggested actions in the Link provided by Jenkins too.