Access server settings in user manual

[lukavdplas]

Is your feature request related to a problem? Please describe.

The user manual needs to provide straightforward documentation for users. However, the user experience can depend on how the server is configured. For example:

• Is UU login an option?
• What are the download limits?
• Is a visualisation/feature actually included in a corpus on this server?

The technical implementation of the manual (stored as static files in the frontend) means that there is no way to check these variables, so the manual may describe features that the server does not support, or needs to be vague about the configuration. (For example, you can mention the existence of download limits but you have to be mysterious about how high those limits are.)

Describe the solution you'd like

The manual should be a practical guide to users of this instance, so that means it should be adaptable.

Technically, that means the markdown files for the manual should be handled in a different way. Suggested implementation:

• Move the manual pages to the backend
• Use the Django template language to implement variables in the manual
• Create API endpoints to retrieve the manual index and individual pages.
• Reuse the DocumentationTemplateField to render the manual contents.
• The ManualComponent does not need to change for this, except that the URLs to retrieve the manual should be changed.

Describe alternatives you've considered

• Implement variables in the frontend, instead of moving documentation to the backend. Possible, but this may require an extra API endpoint to fetch various server settings. (Ones that are not sensitive, of course. E.g. the download limit.) It also requires an implementation to enable template logic in markdown files, while the backend already has that implementation (used for corpus documentation).
• No variables: just describe in the manual that certain things depend on the server configuration. Makes things needlessly complicated for users, who usually don't care about the existence of other I-analyzer instances.