Decouple pulsar

[rigelk]

Please check if the PR fulfills these requirements

• [x] The commit message follows our guidelines
• [x] Tests for the changes have been added (for bug fixes / features)

What kind of change does this PR introduce? (Bug fix, feature, docs update, ...)

The PR allows not specifying a pulsar server in the environment, sticking to the optional status of the value in IEnvironment, and allowing development/deployment scenarios without pulsar.

What is the current behavior? (You can also link to an open issue here)

Pulsar is required, and shown even when not configured as an option for new and existing documents, without any way to disable it.