Move away from aliases to functions

[HenrikBengtsson]

Generalization of Issue #65

set_shell_function(): https://lmod.readthedocs.io/en/latest/015_writing_modules.html#setting-aliases-and-shell-functions

• [x] cluster-utils
• [x] igv
• [x] picard
• [x] mutect
• [x] snpeff
• [x] varscan

Deploy on:

• [x] C4
• [x] wynton