Remove all references to the private property known as "Bitshares Group"

As the "Bitshares Group" is the private property of an individual, it has no place representing the whole Bitshares blockchain.

Remove all links to Bitshares group telegram, twitter, bitsharesdev telegram, and the deranged "bitshares group roadmap".

Frankly these docs are lackluster and primarily serve to prop up an individual's private property and power grab over the community, instead of properly documenting Bitshares future for developers and investors.