Increase Report Key Statistics Decimal Places

[AlexCatarino]

Expected Behavior

Key statistics values have 3 decimal places.

Actual Behavior

They vary from 0 to 1.

Proposed Solution

Move format from Element (e.g.: CAGR):
https://github.com/QuantConnect/Lean/blob/master/Report/ReportElements/CAGRReportElement.cs#L63
to template.
https://github.com/QuantConnect/Lean/blob/master/Report/template.html#L72

Checklist

• I have completely filled out this template
• I have confirmed that this issue exists on the current master branch
• I have confirmed that this is not a duplicate issue by searching issues
• I have provided detailed steps to reproduce the issue