Refactor fleet missions' code | Part 12 | Combat morale updates

[mdziekon]

Summary:

All three possible combat missions (MissionAttack, MissionDestruction & MissionGroupAttack) share almost the same mechanism of combat morale updating. This mechanism should be implemented in just one place and shared among them.

Changelog:

• Export combat morale updating into a separate function
  • Function export (as utility)
  • Use in Regular attack
  • Use in Group attack (ACS)
  • Use in Moon destruction
• Fix United Attacks morale updater, where in cases of significant "stronger" attackers group, the defender would get a morale boost even when the attackers won the battle (defenders should get a boost only when they won or they drawn the battle)
• Unify loading data from morale cache into a variable

Related issues or PRs:

• Refactor fleet missions' code #91