The harvester workers should not run as root

[ahaywardtvuk]

As part of https://github.com/EOEPCA/system-tasks/issues/69 I'm going through the processes running as root on the EOEPCA dev cluster, which includes these:

Namespace	Pod Name	Command
registration-harvester-api	registration-harvester-worker-landsat-bc8ccb4f8-zjhfw	[dpkg-preconfigu]
registration-harvester-api	registration-harvester-worker-landsat-bc8ccb4f8-zjhfw	/usr/local/bin/python /usr/local/bin/fastapi run src/worker/main.py --port 8080
registration-harvester-api	registration-harvester-worker-sentinel-57bd97d595-cn7dk	/usr/local/bin/python /usr/local/bin/fastapi run src/worker/main.py --port 8080
registration-harvester-api	registration-harvester-worker-stac-86dccb4b9c-skw7m	/usr/local/bin/python /usr/local/bin/fastapi run src/worker/main.py --port 8080

To avoid security weaknesses and problems running on platforms with a 'no root' policy, these should run as another user.