Suggestion of change: Link EigensolverTolerance to ConvRelDens

As explained in the documentation, the two variables are related. Should we change the logic such that if ConvRelDens is defined, the default value of EigensolverTolerance is set to 1/10 of it?

This would make the user experience simpler I think, and I think we should do this for the upcoming 16.0 release.

@sohlmann @martin.lueders @AlexBuccheri What do you think about this?