BF: fail2ban.conf reader expected "int" type for `loglevel`

Closes #657
TST: Skip SYSLOG log target test if '/dev/log' not present
TST: Skip badips.py test is no network option set
DOC: Add database settings for fail2ban.conf to jail.conf(5) man page
ENH: Add iptables and firewalld to "After" for systemd service file.

Also remove no longer supported syslog.target.
Closes #658
Merge branch 'database-no-sqlite'

Conflicts:
	ChangeLog
        - Entries added in both branches, both kept
DOC: sphinx documentation