Reorganize developer specs

[TimEvens]

Currently developer schemas/specs are in two places, docs and on the main page under Developer integration. This should be reorganized so that they are in the same place, such as under developer section. The developer section should have:

1. API Documentation (e.g. Message Bus API, MariaDB Schema, and REST API). API documentation SHOULD contain examples as well, so each API might be a section by itself. For example, develop/api/msgbus, develop/api/topomgr, develop/api/db
2. Guides This section would include details of how a developer starts to develop and the options they have. Such as when to use live Kafka verses DB verses Topology Manager.
3. API Bindings - This is a summary page for bindings available. Links should reference the API documentation sections.

API documentation does not document the architecture or component itself. That's documented under component. Each API section should reference the component documentation for easy navigation between them.