Improve Github EOSIO page

[kesar]

https://github.com/EOSIO is the entrance for many new developers, we could improve it with very small tweaks.

• Add logo
• Add url
• Remove pinned Documentation (its outdated)
• Add eosio.cdt
• Add members working in the project?

I think we could have up to 6 pinned repositories:

• eos, eosjs, eosio.cdt, eosio.contracts, demux-js, eosio-project-boilerplate-simple

Some developers end up in https://github.com/EOS

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[mharrisb1]