This updates the various documentation to account  for the modified
subsidy split introduced by by DCP0012.

In particular, the following changes are made:

Issuance docs:

- Updates the text to detail what the subsidy split was prior to
  DCP0010, prior to DCP0012, and after along with exactly which block
  heights the changes took place
- Adds the effective split of the total mined coins taking into account
  the initial block reward split along with the modifications made by
  DCP0010 and DCP0012
- Updates the upper limit on the total supply
  - Updates the reference link to the relevant code accordingly
- Updates the estimated supply table:
  - Includes the modified subsidy split
- Updates the graphical supply chart
  - Includes a dark mode variant of the image

Overview:

- Updates summary table and descriptions to the modified splits

Glossary:

- Description of the Hybrid PoW/PoS section updated to the modified
  splits

Constitution:

- Update the split for Proof of Work
- Update the split for stakeholder votes