Add SecObserve to community integrations

[StefanFl]

Description

The open source vulnerability management system SecObserve has an API integration, to load vulnerabilities from Dependency Track. This is the reason, SecObserve should appear in the documentation for the community integrations.

Addressed Issue

There is no issue at the moment. Do we need one for this?

Checklist

• I have read and understand the contributing guidelines
• This PR fixes a defect, and I have provided tests to verify that the fix is effective
• This PR implements an enhancement, and I have provided tests to verify that it works as intended
• This PR introduces changes to the database model, and I have added corresponding update logic
• This PR introduces new or alters existing behavior, and I have updated the documentation accordingly

[nscuro]

Thanks @StefanFl, much appreciated!