This routine build minBcID for boundary elements, it is required if a
element has more than one boundary in its directions.
if a element has more than one boundary then use minBcID which depends
on boundary order in seeder configuration
Nodes of different colours represent the following:
Solid arrows point from a procedure to one which it calls. Dashed
arrows point from an interface to procedures which implement that interface.
This could include the module procedures in a generic interface or the
implementation in a submodule of an interface in a parent module.