Add editing for level win/lose conditions

[leveleditor]

There could be some pre-defined level win/lose conditions that are the most common. Advanced win/lose conditions would require custom scripting and is out of scope for this issue (future todo).

Win:

• Destroy all enemy units (and/or buildings)
• Destroy or capture enemy base
• Destroy or capture a specific building
• Capture (do not destroy) or build a specific building
• Get a unit to a specific tile (maze level, escort mission)
• Collect a specific amount of credits

Lose:

• Specific unit destroyed (lone saboteur, escort mission)
• Specific building captured or destroyed
• Base destroyed or captured

Additionally the base needs to be "optional" for missions like santa, maze, etc.

[Landlighter]

Will some of these conditions override the current default win condition? Like, if you need to get a unit to a specific tile, but all enemies are destroyed before you do that, will the level keep running?