Add -config option for plot_data_plane to override default plotting options

[JohnHalleyGotway]

Describe the Enhancement

While testing development for #2218, @hsoh-u wanted to modify the map data used by plot_data_plane. Those default map data options (e.g. filenames, line types, line colors) can be found in data/config/ConfigMapData. Since plot_data_plane does not currently read a user-specified configuration file, @hsoh-u had to override the settings in the installed MET_BASE/config/ConfigMapData file. Another option is copying over the entire contents of the installed MET_BASE directory into a new location, modifying ConfigMapData, and setting the $MET_BASE environment variable to point to the new location.

While both options are fine for development, neither is very user-friendly when running a shared installation of MET. Recommend adding a new optional -config command line argument for plot_data_plane. If provide, parse its contents to override any settings read from default config files, including ConfigMapData.

In practice, I would imagine this would ONLY be used to override that map data.

Time Estimate

4 hours

Sub-Issues

Consider breaking the enhancement down into sub-issues.
None needed.

Relevant Deadlines

List relevant project deadlines here or state NONE.

Funding Source

Define the source of funding and account keys here or state NONE.

Define the Metadata

Assignee

• Select engineer(s) or no engineer required
• Select scientist(s) or no scientist required

Labels

• Select component(s)
• Select priority
• Select requestor(s)

Projects and Milestone

• Select Repository and/or Organization level Project(s) or add alert: NEED PROJECT ASSIGNMENT label
• Select Milestone as the next official version or Future Versions

Define Related Issue(s)

Consider the impact to the other METplus components.

• METplus, MET, METdataio, METviewer, METexpress, METcalcpy, METplotpy
• Recommend adding a METplus one to support this new command line option.

Enhancement Checklist

See the METplus Workflow for details.

• Complete the issue definition above, including the Time Estimate and Funding Source.
• Fork this repository or create a branch of develop.
  Branch name: feature_<Issue Number>_<Description>
• Complete the development and test your changes.
• Add/update log messages for easier debugging.
• Add/update unit tests.
• Add/update documentation.
• Push local changes to GitHub.
• Submit a pull request to merge into develop.
  Pull request: feature <Issue Number> <Description>
• Define the pull request metadata, as permissions allow.
  Select: Reviewer(s) and Development issues
  Select: Repository level development cycle Project for the next official release
  Select: Milestone as the next official version
• Iterate until the reviewer(s) accept and merge your changes.
• Delete your fork or branch.
• Close this issue.