Add Environment Modules to Build and software organization tools

Reintroduce Environment Modules software which was removed by 7f947f8.
Removal was due to the project being hosted on SourceForge. Project is
now primarily managed from GitHub.

Also take this opportunity to clarify name of Lmod software (in the same
category).

README.md

@@ -121,7 +121,8 @@ _See also [Restic's list of Linux backup software](https://github.com/restic/oth
 Build and software organization tools.
 
 - [EasyBuild](https://easybuild.io/) - EasyBuild builds software and modulefiles for High Performance Computing (HPC) systems in an efficient way. ([Source Code](https://github.com/easybuilders/easybuild-easyconfigs)) `GPL-2.0` `Python`
-- [environment-modules Lmod](https://www.tacc.utexas.edu/research-development/tacc-projects/lmod) - Lmod is a Lua based module system that easily handles the MODULEPATH Hierarchical problem. ([Source Code](https://github.com/TACC/Lmod)) `MIT` `Lua`
+- [Environment Modules](https://cea-hpc.github.io/modules/) - Environment Modules provides for the dynamic modification of a user's environment via modulefiles. ([Source Code](https://github.com/cea-hpc/modules)) `GPL-2.0` `Tcl`
+- [Lmod](https://www.tacc.utexas.edu/research-development/tacc-projects/lmod) - Lmod is a Lua based module system that easily handles the MODULEPATH Hierarchical problem. ([Source Code](https://github.com/TACC/Lmod)) `MIT` `Lua`
 - [Spack](https://spack.io/) - A flexible package manager that supports multiple versions, configurations, platforms, and compilers. ([Source Code](https://github.com/spack/spack)) `MIT/Apache-2.0` `Python`