Add issues closed line graph and update hovertemplate

[christinaexyou]

@cdolfi Resolves part of https://github.com/oss-aspen/8Knot/issues/468 and https://github.com/oss-aspen/8Knot/issues/470 by making the following changes:

• Adds line for issues closed
• Updates the hover template with Date, indicating the time window for which prolificacy is calculated

[christinaexyou]

@cdolfi Changes made:

• Added issue comment line
• Updated legend labels to be more concise - changed PR Review Comment to PR Comment and PR Request Review to PR Review

[cdolfi]

@christinaexyou let me know when this is ready for re-review. If there is not an obvious way of fixing file wide this @JamesKunstle might have some guidance

[JamesKunstle]

@cdolfi @christinaexyou I'll pull this now and take a look to see if I have any ideas.

[JamesKunstle]

Working on this, though I'm getting a DBReadFailure for some reason, so I may need to spend some time debugging tomorrow before I can actually review this PR.

[JamesKunstle]

@christinaexyou

Review

I pulled your most updated branch and tried the following orgs/repos, but neither 'Issues Closed' nor 'Issue Messages' lines appeared.

'chaoss' org '3scale' org 'kubernetes/kubernetes' repo

This is a screenshot of what I get for 'kubernetes/kubernetes':

And this is my current branch's log:

Which I believe is up to date.

One additional request

I'd love it if the Action Type was in the hover information. That'd make reading the graph much easier.

[christinaexyou]

@cdolfi @JamesKunstle Changes made:

• Reverted formatting
• Issue Closed and Issue Comment line graphs are visible
• Shortened PR Request ... labels to PR
• Updated hover template to display action type

[JamesKunstle]

@christinaexyou Yuh this looks great, gonna merge it.