print more cleanly

[juliasloan25]

Purpose

closes #963

Disable non-root logging instead of checking if root every time we log something

Content

• [x] add disable_logging call to comms context init function
• [x] remove redundant ClimaComms.init calls
• [x] remove now-unused comms_ctx argument from show_memory_usage
• [x] check output of MPI experiments