Chance to ignore min/max or pick invalid Enum should be optional

[jma-qb]

Lain can chose to ignore the min and max bounds of a Vec as well as picking an invalid value for an Enum. see https://github.com/AFLplusplus/lain/blob/main/lain/src/mutator.rs#L19
I believe the user should be able to disable this behavior or chose a different value without cloning the library to set the chance to 0.
As it requires a bit of refactoring of Lain, this behavior should at least be documented/highlighted in a visible place.
I also think the default values are too high.