Run Supported Towers capabilities

[wwieder]

Expand capabilities from run_neon to simulate additional supported tower sites (e.g. PLUMBER2 & AmeriFlux for RUBISCO).

Since we already have surface datasets and datm input for additional tower sites we should be able to build on the run_neon script to automate the generation of spinup, postAD and transient simulations for different tower sites.

From our conversation at the SE meeting it sounds like this could be done by creating the appropriate user_mods directories for each network / tower site and then adding some additional functionality to a more generic run_tower script that facilitates running one or multiple supported tower sites.

@olyson noted that PUMBER has some additional complications because all tower sites:

• Run with local time, meaning they have to initialize the model at different starting times
• Span different time periods, length of records
• Forcing data are at 30 or 60 minute time intervals
• Use LAI stream files for SP simulations (these have also been created)
  @ekluzek suggested this can all be handled by the user_mod directories.

This issue is closely related to #1354, but has more/ updated specifics

[ekluzek]

Adding next to this so that we decide who will be working on this and about when we want this to happen.