ipld: Extract IPLD plugin into separate repository

[Wondertan]

Goal

For ShareExchange and DASing to work we need to use IPLD implementation of NMT, which is currently located in Core. The Node needs to use it as well, so we need to extract the plugin with supporting functions into a separate repo to be used by both Core and Node repos.

Actions

• Create new repo ipld: move IPLD plugin into separate repo #111
• Cherry-pick plugin and ipld package from Preliminary introduction of RowSet with supporting changes celestia-core#427
• Define what logic should be in the repo and what should be part of Node repo.
• Update core and close ipld: consider moving into separate repo celestia-core#296
• ipld: Consolidate parameters used for square size. #114

[renaynay]

@Wondertan can you make the first action item link to #111 ?

[liamsi]

Are we still planning to move this into a separate repo? I think for now we are fine with this living in node (instead of core). Should we close this and revisit once a need arises?

[renaynay]

@liamsi post mainnet likely

[liamsi]

ref: #656

I think we can close this for now. Feel free to re-open if needed.

[Bidon15]

Grooming 12/07/2022:

1. Moving to Post-Mainnet
2. Extraction should be done after ipld: Consolidation with share #878

[Bidon15]

Grooming 01/11/2022:

There is no reason to follow-up/track this issue due to a different approach and core/app won't use it