ADD: reader for mfrsr7nchaod files

[cgodine]

Adding reader for MFRSRAOD files. Will read in a list of filenames, open xarray Datasets of each file, and merge all Datasets along time dimension. Coordinate variable Io_gauss_time will have the union of date values from all read files.

Added mfrsr7nchaod1mich files from SGP C1 to arm-test-data in order to complete testing.

• Closes cftime and open_mfdataset conflict #1018
• Tests added
• Documentation reflects changes
• PEP8 Standards or use of linter
• Xarray Dataset or DataArray variable naming follows 'ds' or 'da' naming

[zssherman]

@cgodine Thanks for the PR! Are these files netcdf? What I'm debating is, if possible, if we would want to integrate this with the current arm netcdf reader or if its possible, or if a separate reader is fine. @AdamTheisen thoughts? Maybe the same process as the current reader, but then a check for these types of files that feeds them through code like we see in this PR?

[cgodine]

@cgodine Thanks for the PR! Are these files netcdf? What I'm debating is, if possible, if we would want to integrate this with the current arm netcdf reader or if its possible, or if a separate reader is fine. @AdamTheisen thoughts?

Yes, they are netcdf (ARM c1-level VAP files). I had thought about integrating with the read_arm_netcdf function, but I believe this is the only ARM data with the rolling window coordinate dimension causing the concatenation issue. I can definitely refactor if that is a more desirable outcome though!