redis: implement XADD stream support

[satta]

• [X] I have read the contributing guide lines at https://docs.suricata.io/en/latest/devguide/contributing/contribution-process.html
• [X] I have signed the Open Information Security Foundation contribution agreement at https://suricata.io/about/contribution-agreement/ (note: this is only required once)
• [X] I have updated the user guide (in doc/userguide/) to reflect the changes made (if applicable)
• [X] I have created a ticket at https://redmine.openinfosecfoundation.org/projects/suricata/issues (if applicable)

Link to ticket: https://redmine.openinfosecfoundation.org/issues/7082

Describe changes:

• Add new xadd/stream option for eve-log.redis.mode setting, enabling sending EVE content to a stream with a configurable name; IDs will be assigned automatically and the field for content will be eve.
• Add documentation for new options.
• Include the specified invalid Redis mode in error message if an unknown mode is configured.