Add minBarLength to chart scales

[lekoaf]

This pull request:

• Adds minBarLength to the X and Y Axis. A new feature in chart.js 2.8.0.
• Adds a test for minBarLength.
• Substantially cleans up the test file. It was all over the place.

Please fill in this template.

• Use a meaningful title for the pull request. Include the name of the package modified.
• Test the change in your own code. (Compile and run.)
• Add or edit tests to reflect the change. (Run with npm test.)
• Follow the advice from the readme.
• Avoid common mistakes.
• Run npm run lint package-name (or tsc if no tslint.json is present).

Select one of these and delete the others:

If changing an existing definition:

• Provide a URL to documentation or source code which provides context for the suggested changes:
  https://www.chartjs.org/docs/latest/charts/bar.html
  Introduce the 'minBarLength' dataset property for bar scales (X or Y) chartjs/Chart.js#5741
• If this PR brings the type definitions up to date with a new version of the JS library, update the version number in the header.
• If you are making substantial changes, consider adding a tslint.json containing { "extends": "dtslint/dt.json" }.

[typescript-bot]

👋 Hi there! I’ve run some quick performance metrics against master and your PR. This is still an experiment, so don’t panic if I say something crazy! I’m still learning how to interpret these metrics.

Let’s review the numbers, shall we?

Comparison details 📊

	master	#37640	diff
Batch compilation
Memory usage (MiB)	72.1	71.8	-0.3%
Type count	10295	10300	0.0%
Assignability cache size	33994	33995	0.0%
Subtype cache size	0	0
Identity cache size	3	3	0.0%
Language service
Samples taken	263	288	+9.5%
Identifiers in tests	263	288	+9.5%
getCompletionsAtPosition
Mean duration (ms)	373.6	351.7	-5.9%
Median duration (ms)	370.5	347.6	-6.2%
Mean CV	14.1%	15.3%	+8.9%
Worst duration (ms)	506.0	490.6	-3.0%
Worst identifier	title	x
getQuickInfoAtPosition
Mean duration (ms)	377.6	354.9	-6.0%
Median duration (ms)	375.8	352.7	-6.1%
Mean CV	15.6%	16.7%	+7.3%
Worst duration (ms)	496.6	470.8	-5.2%
Worst identifier	itemSort	devicePixelRatio
System information
Node version	v10.16.0	v10.16.1
CPU count	2	2
CPU speed	2.294 GHz	2.294 GHz
CPU model	Intel(R) Xeon(R) CPU E5-2673 v4 @ 2.30GHz	Intel(R) Xeon(R) CPU E5-2673 v4 @ 2.30GHz
CPU Architecture	x64	x64
Memory	6.8 GiB	6.8 GiB
Platform	linux	linux
Release	4.15.0-1047-azure	4.15.0-1052-azure

First off, note that the system varied slightly between these two runs, so you’ll have to take these measurements with a grain of salt.

It looks like nothing changed too much. I’m pretty lenient since I’m still an experiment, so take a look anyways and make sure nothing looks out of place.

---

If you have any questions or comments about me, you can ping @andrewbranch. Have a nice day!

[typescript-bot]

@lekoaf Thank you for submitting this PR!

🔔 @anuti @FabienLavocat @KentarouTakeda @larrybahr @mernen @josefpaij @danmana @guillaume-ro-fr @archy-bold @braincore @frabnt @alexdor @mahnuh @Conrad777 @adripanico @wertzui - please review this PR in the next few days. Be sure to explicitly select Approve or Request Changes in the GitHub UI so I know what's going on.

If no reviewer appears after a week, a DefinitelyTyped maintainer will review the PR instead.

[typescript-bot]

Since you're a listed owner and the build passed, this PR is fast-tracked. A maintainer will merge shortly. If it shouldn't be merged yet, please leave a comment saying so and we'll wait. Thank you for your contribution to DefinitelyTyped!

[typescript-bot]

I just published @types/chart.js@2.8.1 to npm.