Allow to keep the build dir after succesful build

Set the option cleanupbuild to False to keep the build dir after a
succesful build. Can be helpfull for debugging purposes.
Added intel & foss toolchains
bump version to v1.12.1dev
make sure that 'module' function with either 'lmod' or 'LMOD_CMD' is accepted as matching with Lmod modules tool
fix bootstrap with Lmod
fix unit test for --allow-modules-tool-mismatch
check whether module is defined before undefining it
fix unit test that checks for module vs modules tool mismatch detection
allow mismatch of modules tool during stage 2 of bootstrap
useless to undefine 'module', subshells may get it redefined anyway
make sure modules/all subdir in install path already exists
Add custom repository type
Merge pull request #911 from boegel/fix_lmod

fix bootstrap with Lmod, fix issue with module function check
make sure that 'module' function with either 'lmod' or 'LMOD_CMD' is accepted as matching with Lmod modules tool
fix bootstrap with Lmod
fix unit test for --allow-modules-tool-mismatch
check whether module is defined before undefining it
fix unit test that checks for module vs modules tool mismatch detection
allow mismatch of modules tool during stage 2 of bootstrap
useless to undefine 'module', subshells may get it redefined anyway