V2 Patch bundling plan

[georgesnelling]

Proposed migration steps for each user

Synthesize user.tag (see tag spec, Issue #444).

Create a new root patch: { name:[user.name], tag:[see tag spec], type:"root" }. User is owner/modifier/creator.
Create link from user to root patch, type = "admin".
For each patch owned by user:

1. create link from sub-patch to root patch, type = 'child'
2. set the _acl property of the child patch to the root patch