Allow for specifying grid properties

[plgbrts]

It appears that grid properties can currently not be defined as static property for inclusion in a flownet (FLOW_REALIZATION.DATA) input file. For, e.g., PVT tables this can be done via a PROPS.INC in the config/*_static folder.

An example of a grid property (for a thermal simulation) in the GRID section is

-- total thermal conductivity
THCONR
6242*112/

A complication of specifying a grid property for a flownet simulation is that a priori the number of grid cells is not known. A suggestion may be to introduce a template file GRID.INC.TMPL with contents (example)

-- total thermal conductivity
THCONR
{{nx}} * 112/

to be processed into a regular GRID.INC include file.