What this MR does / why does DuMux need it:
Adds a few methods for averaging solutions across different grids.
Notes for the reviewer
Also, for the convolutional averaging, the filter implemented is currently only a uniform filter. A gaussian filter could also be cool?
Before you request a review from someone, make sure to revise the following points:
\n character. Make sure there is no
\ No newline at end of file comment in "Changes" of this MR.