Replace User 1000 instead of onyxia

[alexisdondon]

IT seems that's better practice to put USER idUser in a dockerfile.

Some automatic tools like opa with rules can't determine from the image if the user run as root or not because it needs a numerical id instead of a name.

[alexisdondon]

In other words we should change all USER onyxia by USER 1000

[alexisdondon]

72

[alexisdondon]

done