Recent push to <feature/all-handlers> broke missions

[Seltraeh]

After updating how units are stored, I layed the ground work for auto incrementing of units as they are naturally obtained in the game.

With that came several small but important fixes required to make the game work:

1. Summoning, and fallback units still use hardcoded values for unique user unit ID that will need to be setup to auto increment starting at 1000. The reason no unit can be below this had to be set up somewhere in the client. I didn't test how low I can go, but I know starting at 1000 is always safe. I was trying to start at 1 but that kept crashing the game.
2. Maxwell (@Tom2096's unit for missions) was broken and will need to be reimplemented as the user's leader with all of his stats implemented.
3. Units need stats. That is a HUGE undertaking if their stats don't exist somewhere in an MST or in a spreadsheet. I can create the archetecture for the units in the local user's save profile to allow for stat modification, but without unique starting stats, we will be tweaking values to balance characters for a long time. (Almost indefinitely)
4. The alpha mission @Tom2096 made for some reason got busted. Looking at the responses and handlers that made it possible now to fix.