Hard to find the docs/specs for core api

[SidHarder]

Currently the “docs” link on ipfs.io links to docs for http api. Very hard to find the docs/specs for core api

The plan:

1. Make a landing page README in https://github.com/ipfs/interface-ipfs-core/tree/master/API that provides a clear path into the documentation for all the modules
2. Update the readme in https://github.com/ipfs/interface-ipfs-core/ to call out the fact that there are docs, include a link to /API/README.md
3. Update ipfs.io/docs to include a link to the core API docs

[flyingzumwalt]

At the very least, it should link to the info in https://github.com/ipfs/interface-ipfs-core/tree/master/API

[flyingzumwalt]

The plan:

1. Make a landing page README in https://github.com/ipfs/interface-ipfs-core/tree/master/API that provides a clear path into the documentation for all the modules
2. Update the readme in https://github.com/ipfs/interface-ipfs-core/ to call out the fact that there are docs, include a link to /API/README.md
3. Update ipfs.io/docs to include a link to the core API docs