Permissions for custom metadata

[vmario89]

Problem or motivation

This is another request i made at the old sismics docs, still seeing this as relevant:

using metadata it would be useful to configure who can see what metadata. I have a set of metadata which information i dont want to share with all users but with a subset of groups/users. Would be a helpful enhancement

When sharing to less privileged users, quite sensitive metadata could be hidden for them

sismics#409

Proposed solution

for each metadata field, introduce permission sets READ/WRITE, indentically as tags behave

Alternatives considered

No response

[fmaass]

I accept this, but not as a quick change. Per-field read and write permissions extend the permission model itself. I will not rush this between patches, so it sits on the longer-term major line with the other deep changes to that model.