Decouple DAS from celestai-core

[evan-forbes]

Summary

Since we decided to delegate DAS to celestia-node, we should remove this functionality in celestia-core.

Details

Per ADR 007, there have been extensive changes made to incorporate DAS into our fork of tendermint. Most of these changes will need to be reverted, and what remains should either be refactors so that it doesn't import celestia-core, moved to celestia-node, or moved to it's own repo.

Action Items

• Move consts, ipfs, and ipld to pkg #508
• Stop embedding an IPFS node #514
• Remove IPFS code  #523
• Remove the DataAvailabilityHeader from the Proposal #518

References

tracking issue #491
ADR #504

[evan-forbes]

While there is still some minor refactoring we could do (see #505), since #523 was merged, we have purged DAS from celestia-core and this issue can be closed.