added guidelines for flight planning

[bjorn-stevens]

I wasn't sure about where and how to put this in the doctored... or how the header information should be included in the markdown, but hopefully this creates something that can be amended and included with minimal effort

[lkluft]

I wasn't sure about where and how to put this in the doctored...

I moved it to orcestra_book/plans/howto.md. This way, the official URL will be http://orcestra-campaign.org/plans/howto which is simply nice to read.

or how the header information should be included in the markdown,

We only need the orphan: true settings which tells Sphinx to not worry about the fact that the document is not included in the table of contents; we do reference it manually.

but hopefully this creates something that can be amended and included with minimal effort

Technically, it is included now 👍 If Cathy is fine with the content, we can merge

[chohenegger]

One thing that was not clear to me was if this was a description of the flightplan for the pilot, or for the information we need to give FX (which e.g. follows a different way to write lat/lon) or for the flightplan we put on internet. Shouldn't we describe all the steps? Or are there somewhere else. Also, I thought that the day before often meant 10, at least for ATC

[chohenegger]

@bjorn-stevens the coordinates are written in the wrong way for the pilot

[bjorn-stevens]

Checked with Cathy, this is now ready.