Migrate to Node 12 and npm 7, remove deprecated dependencies

[nblagoev]

• Build using Node 12, since Node 10 is end-of-life at 30/04/2021
  
• Bump all dependencies to latest to remove any deprecated packages
• Migrate to npm 7
  • Yarn 1 is in maintenance mode and the vscode extension publisher (vsce) is not compatible with Yarn 2 due to inability to produce list of production dependencies
  • npm 7 has greatly improved its speed and the ability to do deterministic and reproducible builds
  • npm 7 has support for workspaces which we can leverage when open-sourcing the rest of the vRBT components
• Fix eslint rule and formatting warnings throughout the code base

[codecov]

Codecov Report

Merging #95 (dfdebd1) into master (a15ad4b) will decrease coverage by 0.06%.
The diff coverage is 60.00%.

@@            Coverage Diff             @@
##           master      #95      +/-   ##
==========================================
- Coverage   50.18%   50.12%   -0.07%     
==========================================
  Files          42       42              
  Lines         805      806       +1     
  Branches      113      113              
==========================================
  Hits          404      404              
- Misses        399      400       +1     
  Partials        2        2