Add Subject prefix filtering support

[ludovic-boutros]

• Please check if the PR fulfills these requirements

• [x] The commit messages are descriptive
• [x] Tests for the changes have been added (for bug fixes / features)
• [x] Docs have been added / updated (for bug fixes / features)
• [x] An issue has been created for the pull requests. Some issues might require previous discussion.

• What kind of change does this PR introduce? (Bug fix, feature, docs update, ...) This PR introduce the support of subject prefix filtering.

• What is the current behavior? (You can also link to an open issue here) Currently it is not possible to define which subjects should be managed.

• What is the new behavior (if this is a feature change)? As we can do with topics and groups, with this PR, we can now manage which subjects should be managed using prefixes.

• Does this PR introduce a breaking change? (What changes might users need to make in their application due to this PR?) No

Fix #526.