NO TICKET: organize API endpoints and documentation

[jacob-a-brown]

Why

This PR addresses the following problem / context:

• To make the OpenAPI documentation easier to understand the routers should be in their own well-defined sections.
• It should also be easy to scroll through the documentation and find the router/collection of endpoints needed

How

Implementation summary - the following was changed / added / removed:

• lexicon and sample were missing tags that have now been added
• Order the routers alphabetically for easier access

[jacob-a-brown]

I noticed that tags were missing from lexicon and sample as I was reviewing the sample endpoints/router and looked at the /docs of the hosted API (locally). This is a short and quick fix.