Merge branch 'feature-flexible-install-paths' into 'develop'

Allwmake

etc/bashrc

etc/config.csh/unset

etc/config.sh/unset

etc/cshrc

src/Pstream/Allwmake-mpi

src/parallel/decompose/Allwmake-mpi

wmake/rules/General/module-path-group

wmake/rules/General/module-path-prefix

wmake/rules/General/module-path-project

wmake/rules/General/module-path-user

wmake/scripts/AllwmakeParseArguments

wmake/scripts/wmake.cmake-args

wmake/scripts/wmake.wmake-args

wmake/wmake