Standalone mode

[ymgyt]

Overview

Currently, syndicationd needs both synd_api and kvsd to run.
For single-user scenarios, setting up these extra components places an unnecessary burden on the user.
I propose adding a standalone mode that works with just the synd_term executable.

Benefits of stand-alone mode

• Authentication can be omitted.

Trade-offs

• Automatic cache updates will no longer be available.

Implementation idea

• Replace kvsd with an embedded SQLite database.