Verify resolution of local plug-in + rules

[nikku]

Proposed Changes

Related to #81, this PR ensures there is a tested scenario available that shows how rules can be provided locally as part of an application. The solution is straight forward:

• Develop your rules in a sub-directory of your application, as if it was a bpmnlint plug-in
• Link (alias) the folder in your main application package, i.e. call it bpmnlint-plugin-local
• Reference the plug-in as local in wherever places you need
• 💰

Checklist

To ensure you provided everything we need to look at your PR:

• Brief textual description of the changes present
• Visual demo attached
• Steps to try out present, i.e. using the @bpmn-io/sr tool
• Related issue linked via Closes {LINK_TO_ISSUE} or Related to {LINK_TO_ISSUE}

[barmac]

LGTM. I think the setup using stock plugins capabilities works just fine.