Try to make this entire application async

Try to make this entire application async

We will need this so that we won't run out of database file descriptors
as psycopg3 currently can only use select() which does not support a
file descriptor to have a number over 1024.

We will also need this to scale this application better. However,
Tornado has some limitations in its template engine which is why we will
need to replace the template engine with Jinja.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>