Update with new separated repositories

[Radivarig]

Some new repos are being created based on this issue.

• [ ] learn
• [x] spacetime
• [ ] visualization
• [x] URE
• [ ] miner
• [ ] pattern-index
• [x] attention
• [x] cogserver
• [x] PLN
• [ ] relex
• [x] generate
• [ ] atomspace-cog

[Radivarig]

@vsbogd added packages from your comment to the list, thanks