Create landuse transition ruleset subsection for the namelist options

[glemieux]

Is your feature request related to a problem? Please describe.
This is necessary per the new namelist addition in ESCOMP/CTSM#3728

Describe the solution you'd like
A table with a description of the clearning matrix settings for each numbered namelist option

Describe alternatives you've considered
None

Additional context
The user may benefit with a reference to https://doi.org/10.5194/gmd-13-3203-2020.

[glemieux]

This also warrants adding to the "Land Use and Harvest" page given the large number of ruleset options.