Implement Anchors

[lthibault]

Tasks

• Define Go interface for Anchor type
• Implement Anchor fields for client.Node
• Implement anchor.Host (cluster host)
• Implement anchor.Ref (memory cells)

Factoring of Anchor has changed in the meantime.

Related Issues

The following issues are related to the task of implementing Anchors. Some of these may no longer be relevant.

• Stream Anchor capabilities when iterating over cluster view #40
• Implement Get/Set operations on anchors #34