Currently the default suricata.yaml sets some values that do not
reflect the default values in the code. As most users are probably
using a default suricata.yaml, make the code have the same defaults as
in suricata.yaml:
- mime.decode-mime: false -> true
- mime.decode-base64: false -> true
- mime.decode-quoted-printable: false -> true
- mime.extract-urls: false -> true
Issue: #5823