TFChain 2.8 improvements (June 20)

[despiegk]

• [x] 3.0 farming needs to work with TFGrid 2.x
• [x] hardening of Binance smartchain bridge
• [x] persistent storage for our bridges and make sure HA ok

[sasha-astiadi]

needs reestimation

[sasha-astiadi]

unvesting being put to later because the pricing hasnt been up to average of 0.1 , and we have more urgent issues to do https://github.com/threefoldtech/home/issues/1113