Add a Configuration page to the documentation

[Zeitsperre]

This adds a configuration page to the documentation

Related issue #18

Changes

• Added page showcasing how to configure your esgpull environment
• Reorganized the setup page to show setup commands after installation steps
• Using the shell directive and $ before all commands for docs clarity
• Added a note about a potential bug that can occur when configuring environment

Discussion

I figured it would be good to add some examples on how to enable downloads and modify configurations to the documentation. There are a few other use cases I would like to have clarified before I can add them to the docs. Will open issues accordingly.

[svenrdz]

Thank you for the contribution @Zeitsperre I made a few suggestions, mostly to clarify the login situation, which is only mandatory for a subset of the ESGF data.

Also, for the new configuration page to appear in the deployed documentation, you may want to add a line to the file docs/mkdocs.yml. It should be under nav at the beginning of the file and mention the filename configuration.md with a title for the table of contents.

Thanks again, I appreciate the help and feedback!

[Zeitsperre]

@svenrdz

Thanks for the reminder that the page should be added to the builder. My documentation engine is typically Sphinx, so I'm not as familiar with mkdocs.

The suggestions you mentioned aren't visible in the PR; Could it be that you haven't yet submitted your comments?

[svenrdz]

I think my suggested changes are visible now, thanks for pointing it out. I'm not yet familiar with all the fancy features of Github.

[Zeitsperre]

Accidentally double-committed a changed. Reverted via force push.