Calculate migration time maps for all co2 mass phases

Issue #401 is about making migration time maps for co2 total mass. We can also make migration time maps for co2 mass in the following phases:
- Dissolved in water
- Dissolved in oil
- Gas
- Free gas
- Trapped gas

We have initially disregarded this, since we for all phases (possibly except "free gas") have a corresponding property used in the calculation of that phase, that can be used for migration time instead of the co2 mass. For instance, migration time maps for "co2 mass dissolved in water" will basically just show the same picture as migration time maps for AMFG.

Note that we currently don't have migration time maps for free and trapped gas (see issue #414).