Firewall Integrations | Support Additional Syslog Formats

Continuing the work started in #3377

Address these firewall integrations to ensure each is consistent in the syslog formats supported.

**Fortinet**
Syslog configuration now includes the option to enable RFC5424 format. Docs [here](https://docs.fortinet.com/document/fortigate/7.0.0/cli-reference/456620/config-log-syslogd-setting).
- [ ] RFC5424

**Juniper SRX**
- [ ] RFC3164

**Sophos XG**
Device Standard Format isn't a standard syslog format according to [their docs](https://docs.sophos.com/nsg/sophos-firewall/18.0/Help/en-us/webhelp/onlinehelp/AdministratorHelp/SystemServices/LogSettings/SyslogServerAdd/index.html). Fine to limit our support to Central Reporting Format.
- [ ] RFC3164
- [ ] RFC5424