add optional FTP setup

[tomkralidis]

User story

As a wis2box user, I want wis2box to be able to accept data upload via FTP, so that I can upload my data in a lower barrier fashion.

Acceptance criteria

• optional docker setup for FTP (ProFTPD)

Definition of done

• unit/functional tests added/updated
• documentation updated
• live demonstration provided

[maaikelimper]

I've added a separate repository for this feature here: https://github.com/wmo-im/minio-ftp-forwarder

I've tested this on the physical wis2box WMO has started to prepare for Zimbabwe

[maaikelimper]

add the option of using 'minio-ftp-forwarder' to our documentation describing data ingestion options

[tomkralidis]

@maaikelimper to add optional docker compose setup in docker/

[maaikelimper]

I need to do some more work to test and prepare standalone images and a docker-compose that reference environment variables from wis2box, to be bumped to sprint-009

[maaikelimper]

I've prepared the image for wis2box-ftp which is now available as ghcr.io/wmo-im/wis2box-ftp published through GHA from https://github.com/wmo-im/wis2box-ftp

I'm wondering how to add this as an option to wis2box, I could introduce another flag '--ftp' so a user could start wis2box with:
python3 wis2box-ctl.py --ftp start
similar to the '--ssl' option I introduced in 'SSL everywhere'.

@tomkralidis , I'm not sure you agree with this way of adding services to the wis2box-docker-compose-stack. Do you have other ideas how you would like to organize this?

[tomkralidis]

As an extra, I think we should document this in wis2box for optional FTP forwarding workflows, with steps on how to run wis2box-ftp. I don't think this needs to be supported by wis2box-ctl.py proper.

[tomkralidis]

Implemented in #409

[tomkralidis]

To test in a future iteration.