Rename ZMQ plugin

[mavam]

📔 Description

The PR renames the ZeroMQ plugin from zmq-app to zmq. For one, the dash caused bugs in combination with Dynaconf and configuration (zmq-app vs zmq_app). Moreover, the suffix -app is a bit confusing because it's technically a plugin.

📝 Checklist

• All user-facing changes have changelog entries.
• The changes are reflected on docs.tenzir.com/threatbus, if necessary.
• The PR description contains instructions for the reviewer, if necessary.

🎯 Review Instructions

TBD

[lava]

Maybe we can use this PR for renaming pyvast-threatbus -> vast-threatbus as well, if we're doing breaking changes anyways.

[dominiklohmann]

Maybe we can use this PR for renaming pyvast-threatbus -> vast-threatbus as well, if we're doing breaking changes anyways.

I'll do that in a separate PR so we have an easier time adapting downstream.

[lava]

The changes are just mechanical, and we already verified experimentally that we didn't miss anything.

Note to self: We need to publish the package under the new name to PyPi when merging this.