* give a rule of thumb for update time in the documentation
* log the SQLite3 version, which can affect performance
* do the vacuum in non-WAL mode, to correctly set the page size and to
avoid very slow behavior on older SQLite3 versions. Larger page sizes
are generally faster (including subsequent vacuum operations).
This won't help much for the first vacuum after this change, but it
will help afterward.
* likewise, set the page size properly on "moonfire-nvr init".
Besides being more clear about what belongs to which, this helps with
docker caching. The server and ui parts are only rebuilt when their
respective subdirectories change.
Extend this a bit further by making the webpack build not depend on
the target architecture. And adding cache dirs so parts of the server
and ui build process can be reused when layer-wide caching fails.
