Remove static sectors

[Fabien-B]

As suggested in #2677, I propose here to remove static sectors. All sector will be dynamic ones.

[fvantienen]

I fully agree, this also removes the problem with the correct orientation.

[gautierhattenberger]

I also agree, but maybe one little thing: we should keep the DTD unchanged for some time and print a warning with a deprecated message when using type. People with personal flight plans should have some time to fix them if needed.

[Fabien-B]

I suggest making it an error, so people will take care of the problem before the DTD change.
Running now in Error: attribute "type" on tag sector is deprecated and must be removed is better than not paying attention to a warning, and running in a few weeks in a n obscure DTD error.

[fvantienen]

I agree with the error, this forces people to update their files.

On a side note, shouldn't we list those deprecations somewhere with a specific enddate and a link to the specific code to remove/update. This reminds both the user and maintainers to update/remove this code. So my advice is to do the following:

• Remove all code that is labeled 'deprecated' for more than 1 year or add them to the list
• For new deprecations like this, add them to a list in a file somewhere with a specific enddate

[Fabien-B]

Maybe we can use this github action, together with issues for that?
https://github.com/marketplace/actions/due-dates
And we can also set a "deprecation" tag to these issues so people can find them easily.

[fvantienen]

For me that seems fine 👍 What do you think @gautierhattenberger ?

[gautierhattenberger]

we can give a try until github have a proper "due date" option for pull requests

Here, we have also moved the definition of sectors outside the NAV_C part, so you can use that anywhere in the code and don't need the (dangerous) workaround to define NAV_C twice.

[fvantienen]

Seems fine 👍