This commit configures *bw0.pyrocufflink.blue* as a BURP client, so that
the Bitwarden data can be backed up. A pre-backup script is used to
take a consistent snapshot of the SQLite database before copying it to
the BURP server.
The *burp-client* role installs and configures a BURP client. It should
support RHEL/CentOS/Fedora and Gentoo.
To manage the client password and other server-mandated configuration,
the role uses Ansible's delegation feature to generate a configuration
file in the "clientconfdir" on the BURP server.
An hourly cron task is scheduled that runs `burp -a t` every hour. This
allows the server to configure backup timebands and intervals.