v0.8.0: Merge pull request #2063 from fetchai/develop

• Adds support for protocol dialogue rules validation
• Fixes url forwarding in http server connection
• Revises protocols to correctly define terminal states
• Adds a build command
• Adds build command support for libp2p connection
• Adds multiple fixes to libp2p connection
• Adds prometheus connection and protocol
• Adds tests for confirmation AW1 skill
• Adds oracle demo docs
• Replaces pickle with protobuf in all protocols
• Refactors oef models to account for semantic irregularities
• Updates docs for demos relying on Ganache
• Adds generic storage support
• Adds configurable dialogue offloading
• Fixes transaction generation on confirmation bugs
• Fixes transaction processing order in all buyer skills
• Extends ledger api protocol to query ledger state
• Adds remove-key command in CLI
• Multiple tac stability fixes
• Adds support for configurable error handler
• Multiple additional tests to improve stability
• Multiple docs updates based on user feedback
• Multiple additional tests and test stability fixes