feat: new system API to retrieve liquid cycle balance of a canister

[mraszyk]

This PR implements a new system API ic0.canister_liquid_cycle_balance128 returning the current amount of cycles that is available for spending in calls and execution without getting frozen. This way, canisters can bound the amount of cycles attached to a call to prevent spurious traps when calling ic0.call_cycles_add or ic0.call_cycles_add128.

[berestovskyy]

It's a big PR, and I don't have a single comment! Well done, Martin!

[mraszyk]

@berestovskyy I realized that I had to fix the universal canister in this commit: the binary length of the representation of an inter-canister call's payload in the input to the universal canister might not match the binary length of the actual payload (because the actual payload is only assembled at runtime by the universal canister from its input) and thus I've replaced the operation CallCyclesAddMax by the operation CallDataAppendCyclesAddMax which combines assembling the actual payload and attaching the maximum amount of cycles (knowing the actual paylod's length from the previous step and taking the method name length from an additional input to this operation).