Kusama CC-3 v0.7.0

Initial release for Kusama CC-3 network client. Contains several breaking changes and fixes from 0.6 series/CC-2.

Runtime changes:

• Sessions/epochs are 1 hour not 4 hours. (#630)
• Enable governance transactions (#628)

Runtime changes (Substrate):

• Commission is stated as percent of rewards (paritytech/substrate#4243)
• Use raw public key instead of compressed (paritytech/substrate#4234)
• Safe multi-era slashing for NPoS (paritytech/substrate#3846)
• Validators don't get slashed for offlineness until 10% at once (paritytech/substrate#4232)

Client changes:

• New chain spec (#632)
• Enable refactored authority discovery (#624)
• Move propose_with into a dedicated blocking threadpool (#614)

Client changes (Substrate):

• Check in block authoring that we can author with current authoring version (paritytech/substrate#4201)
• Check block CLI command (paritytech/substrate#4240)
• Handle Grafana server bind errors gracefully. (paritytech/substrate#4241)
• Recover transaction pool on light client (paritytech/substrate#3833)
• Back-off block proposal (paritytech/substrate#4235)
• Implement all storage after prefix (paritytech/substrate#4227)
• Add SHA2-256 hash function (paritytech/substrate#4218)
• Make block proposing remaining duration configurable (paritytech/substrate#4215)
• Add graphs for each function name (paritytech/substrate#4214)