Fix for supply calculation

[Alumn0]

Description

Since the first halving at block 7,000,000 the formular to calculate the current supply is incorrect.
These changes correct the supply calculation by adding a function, which considers the RewardReductionInterval value.

Type of change

Please select the right one.

• [ x ] Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update
• This will require a HardFork to be enabled

Which part is impacted ?

• Wallet
• [ x ] Daemon
• Miner
• Explorer
• Simulator
• Misc (documentation, comments, text...)

Checklist:

• [ x ] I have performed a self-review of my code
• [ x ] I have commented my code, particularly in hard-to-understand areas
• [ x ] My changes generate no new warnings

License

Im am contributing & releasing the code under DERO Research License (which can be found here).