[Structure] Reorganize code/logic from canopy driver to separate submodules

[drnimbusrain]

Need to move and reorganize significant amount of code/logic from driver and consolidate in their own submodules. Some locations (based on current develop branch) where this is needed is as follows (with suggested module names):

1. Pull out all physical calculations to separate subroutines:
   canopy_griddx_mod.F90: https://github.com/noaa-oar-arl/canopy-app/blob/develop/canopy_driver.F90#L189 (Also improve the dx calculation to be dependent on grid cell lat/lon using haversine formula for distance between two points).
   canopy_foliage_mod.F90: https://github.com/noaa-oar-arl/canopy-app/blob/develop/canopy_driver.F90#L255
   canopy_flameh_mod.F90: https://github.com/noaa-oar-arl/canopy-app/blob/develop/canopy_driver.F90#L288

2. Could also make a netcdf_io module based on NACC to read netcdf inputs: https://github.com/noaa-oar-arl/NACC/blob/master/parallel/src/netcdf_io_mod.f90
   canopy_txt_io_mod.F90 (for inputting/reading text file data)
   canopy_netcdf_io_mod.F90 (for inputting/reading netcdf file data)

3. After Issue Adding NetCDF Input/Output File Options #22 is completed, the output creation could be moved to txt and netcdf output modules:
   canopy_outncf.F90: Based on NACC: https://github.com/noaa-oar-arl/NACC/blob/master/parallel/src/outncf.f90
   canopy_outtxt.F90: https://github.com/noaa-oar-arl/canopy-app/blob/develop/canopy_driver.F90#L333

4. After Issue [Structure] Adding Config Types  #21 is completed, anything else about choosing which things to calculate based on the config or calling computation routines could be consolidated into a subroutine to call on the inputs and config:
   canopy_input_mod.F90: https://github.com/noaa-oar-arl/canopy-app/blob/develop/canopy_driver.F90#L278

@zmoon
@drnimbusrain

[zmoon]

#30 is the first go at addressing this

A future PR will further it, see these comments/threads:
#30 (review)
https://github.com/noaa-oar-arl/canopy-app/pull/30/files#r999732896
https://github.com/noaa-oar-arl/canopy-app/pull/30/files#r999774471
https://github.com/noaa-oar-arl/canopy-app/pull/30/files#r999773963
#30 (comment)

[drnimbusrain]

@zmoon I think we have at least in part addressed this organization with latest changes, and with your move from orphaned subroutines to submodules. Do you agree we should close this issue?

[zmoon]

There is still a bit more to do here, so let's wait to close, thanks.

[drnimbusrain]

@zmoon Any further insight into the notes we discussed briefly here, would be helpful before embarking on this and #32 and #21 issues to restructure code to with more streamlined/APIs, config types, modules, and CCPP interface/drivers. Thanks Zach! Just need some other comments or potential helpful code analogs to get a better start. Thanks!