Additional CTA chance balancing, new ambition icon

- Professional-looking CTA ambition icon from AnaxXiphos to supercede my placeholder icon.
- Rolled-back CTA combat impulse chance base weight reduction to -20% rather than -40%.
- Partially countervailing the higher chance for players is a new flat bonus of 33% to the random weight given to all AI characters with a CTA ambition selected.
- A few more fine-grained tiers of martial attribute correlation were also added, FWIW, but the rest is mostly comment block clarification/cleanup.

It looks like this is the right branch to initiate a pull request to at the moment, as you've integrated everything, and this should make it into 3.4.1, and for whatever reason, the diff against your beta is currently re-implementing your payment-by-half commit.