Separate file format documentation from parameters.md

[dlebauer]

The first step in this issue is to decide if it is a good idea and whether to do it.

In the interest of organizing docs, I propose we

• 1. separate out file format docs from parameters.md into an "Input and Output File Formats" page
• 2. add or link to examples.
  • Maybe this is only necessary for sipnet.param (and perhaps compile time flags if any will remain) and less important for met, event, and output time series that just repeat the same things. but for e.g. sipnet.param it seems that having an example would be useful.
  • Could be a link to an exemplar parameter file like tests/sipnet/test_sipnet_infrastructure/standard.param ... see Revamp unit tests after #78, #80, #83 are complete #102