Documentation tasks

[eric-czech]

TODOs related to documentation:

• [x] Separate commands in README into those that produce minimal results and those that are useful on-demand (i.e. monitoring and scaling commands)
• [x] Add separate GKE and DCP instruction sections
• [ ] Add a diagram explaining how the different clusters and client machines relate to one another
  • This isn't really necessary, but I always appreciate any info like this in pipeline docs since maintainers often assume it as common knowledge
• [ ] Add some nice visual from snakemake --dag

[eric-czech]

For reference:

snakemake --default-remote-provider=GS --default-remote-prefix=rs-ukb --dag | dot -Tsvg > dag.svg

currently produces: