GUI real-time graph

[natenog]

Develop the frame for the real-time graph(s) in the wxWidgets application.

[natenog]

Initial graph panel with resizable 2D axes and coordinate grid was merged in #32.

Next steps:

• Implement static graph
  • Establish access to data storage buffer(managed by Backend)
  • Implement "Update graph" button that scans data storage for new data after last collected timestamp
  • Add new data to graph and scale axes accordingly
  • Update last collected timestamp for reference when updating graph again

[natenog]

Real-time graph using wxMathPlot was implemented in commit f9d04a5 and merged to main through PR #60. Graph optimizations will be filed as separate tasks. Closing issue.