20210709b_glerum

New: There is now a geometry model plugin "chunk with lithosphere boundary indicators" 
that allows for two different types of boundary conditions on the side boundaries
of a chunk domain. On each side boundary, two boundary indicators are available
to set these different boundary conditions. A use-case can be prescribed plate motions
on the upper part of the domain and an open boundary underneath the plates. 
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(Anne Glerum, 2021/07/09)