Convert RODBC connections to RMySQL

[lockefox]

Remove ODBC dependency to direct SQL connection. Will make cross-platform portability easier in the long term.

[lockefox]

• Add SQL profile sections to ProsperSlides.cfg
• Convert R_templates/ to reference db by-name
• Add SQL credential mapper to Plotting.py (bulk insert into R template?)
• Add connection tester to Tests/test_plotting.py
• Add Plumbum CLI hooks to help update cfg file