FileReader module

[juliasloan25]

Create a module for reading in data from files, which may contain data at one or multiple points in time. This code was restructured for the ClimaLSM version to have a more logical structure and cleaner layout. In our implementation here, we want to develop more similarly to the ClimaLSM approach. Reconciling these two versions may result in this module requiring more work than the other modules since they differ more between the two repos.

Note: The nans_to_zero function of ClimaLSM's Regridder module should be moved to the FileReader module, along with new missings_to_zero and clean_data functions. https://github.com/CliMA/ClimaLSM.jl/blob/main/src/shared_utilities/Regridder.jl#L13

ClimaCoupler.jl BCReader module: https://github.com/CliMA/ClimaCoupler.jl/blob/main/src/BCReader.jl
ClimaLSM.jl FileReader module: https://github.com/CliMA/ClimaLSM.jl/blob/main/src/shared_utilities/FileReader.jl

ClimaCoupler.jl BCReader tests: https://github.com/CliMA/ClimaCoupler.jl/blob/main/test/bcreader_tests.jl
ClimaLSM.jl FileReader tests: https://github.com/CliMA/ClimaLSM.jl/blob/main/test/shared_utilities/file_reader.jl

tracked by #39