Update to v0.16 (would've been v16)

[balqaasem]

Changelog:

1. Introduce SZ-SNARKs based ZK-SCENE: Replace the TEE based system STEM with a SZ based system ZK-SCALE(Zero Knowledge Setheum Cloud Actuation Layer Engine).
2. Introduce SUVE - pronounced /su:fi:/, SUVE(Setheum Unified Virtual Environment) is an environment that unifies the EVM and the WASM contracts pallet and their account systems. More on the whitepaper.
3. Introduce Shielded Smart contracts on Setheum Cloud.
4. Introduce ZK-ARAB(more on it in its own whitepaper);