fixed file size check for outputs

[cehbrecht]

Overview

This PR fixes the file size check for outputs.

The creation of an output with metalink failed when the output file exceeded the maxsingleinputsize value.

• updated docs
• fixed exception catch of FileSizeExceeded
• using https://pypi.org/project/humanize/

The root cause for this error is fixed in the PR #581.

Related Issue / Discussion

Fix #571

Additional Information

Contribution Agreement

(as per https://github.com/geopython/pywps/blob/master/CONTRIBUTING.rst#contributions-and-licensing)

• [ ] I'd like to contribute [feature X|bugfix Y|docs|something else] to PyWPS. I confirm that my contributions to PyWPS will be compatible with the PyWPS license guidelines at the time of contribution.
• [ x] I have already previously agreed to the PyWPS Contributions and Licensing Guidelines

[cehbrecht]

tests have troubles with gdal installation ...

[coveralls]

Coverage remained the same at 0.0% when pulling 49c3d37988127cd50a6ee76f14e74ed1bf654715 on cehbrecht:fix-filesizeexceeded into bbca1e42b63cf9c31c40fa3e2a731a1528adb2b9 on geopython:pywps-4.4.

[cehbrecht]

Test CI was using ubuntu-latest with is now using gdal=3. As workaround I'm using ubuntu-18.04.

I open an issue for gdal to solve separately ... well, already there #398.

[cehbrecht]

The cause for FileSizeExceeded was probably an unwanted download when using metalink with URL items. So I can remove the new parameter maxsingleoutputsize ... is is not necessary. See #581.

[cehbrecht]

@huard @Zeitsperre merged. Need a patch release on monday. Please complain ... we can fix it with another patch release :)