Release/6.8.0

[ifrit98]

• Introduces SubnetsAPI abstract interface to facilitate a standardized request layer across subnets Bittensor shared request layer #1698
• Add flake8 to bittensor circleci tests CI: Flake8  #1701
• More efficient extrinsic creation in subtensor, specifically for set_weights to minimize priority too low errors. Extrinsic update #1703
• logging.off() switch in bittensor to turn off all logging (and turn it back on with logging.on) logging off switch #1704
• Add no_prompt argument to help printout Add no_prompt argument to help printout #1707
• Adds mypi typechecking to circleci CI: Adds mypy to typecheck during circle ci checks #1705
• Remove set weights ttl now that we have a better extrinsic method
• Bug fix in overview command for dereg stake with outdated stake_info object fields update stake_info fields that caused exception in dereg stake calc #1712
• Moves mock wallet creation to temp dir fix: Moves test wallets to tmp directory  #1711