Acceptance Criteria:

• Determine what the options would be in the chart definition for symbol size and shape
• Implement support for the symbol size option
• Implement support for the symbol shape option

Notes:

See comments in https://phabricator.wikimedia.org/T371758

Also see:

• https://en.wikipedia.beta.wmflabs.org/wiki/Template:Graph:Chart
• https://en.wikipedia.beta.wmflabs.org/wiki/Template:Graph:Chart/testcases
• https://en.wikipedia.beta.wmflabs.org/wiki/User:Pietrasagh/sandbox/symbols_size