[TaskManager] Add TaskManager doc to FF.com

[scottn12]

Description

This PR adds a document overviewing TaskManager to the "Data Structures" section of fluidframework.com.

Reviewer Guidance

I would appreciate feedback on:

• Document structure / flow
• Confusing wording / general editing choices
• Questions you may have after reading this with minimal or no knowledge of TaskManager

Other information or known dependencies

AB#1469

[github-actions[bot]]

🔗 Found some broken links! 💔

Run a link check locally to find them. See https://github.com/microsoft/FluidFramework/wiki/Checking-for-broken-links-in-the-documentation for more information.

linkcheck output

> [email protected] linkcheck /home/runner/work/FluidFramework/FluidFramework/docs
> npm run linkcheck:fast -- --external


> [email protected] linkcheck:fast /home/runner/work/FluidFramework/FluidFramework/docs
> linkcheck http://localhost:1313 --skip-file skipped-urls.txt "--external"

Crawling...

http://localhost:1313/css/style.min.8af3ed4d95c1f1a10c809b4ec3dbfa7f8ee65ac5b520d1dd137999325c0808fd.css
- (1:1031) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/light/latest.svg (HTTP 503)
- (1:1184) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/semilight/latest.eot (HTTP 503)
- (1:1272) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/semilight/latest.eot? (HTTP 503)
- (1:1740) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/semilight/latest.svg (HTTP 503)
- (1:2427) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/normal/latest.svg (HTTP 503)
- (1:3130) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/semibold/latest.svg (HTTP 503)
- (1:3286) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/bold/latest.eot (HTTP 503)
- (1:3811) url(...) => https://c.s-microsoft.com/static/fonts/segoe-ui/west-european/bold/latest.svg (HTTP 503)

http://localhost:1313/docs/apis/core-interfaces/ifluidcodedetailscomparer-interface
- (892:360) 'Array.sort' => https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#Description (HTTP 200 but missing anchor)
- (903:168) 'https://..' => https://github.com/npm/node-semver#usage (HTTP 200 but missing anchor)
- (911:25) 'Array.sort' => https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#Description (HTTP 200 but missing anchor)
- (957:25) 'https://..' => https://github.com/npm/node-semver#usage (HTTP 200 but missing anchor)

http://localhost:1313/docs/apis/core-interfaces/ifluidcodedetailscomparer-interface/
- (892:360) 'Array.sort' => https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#Description (HTTP 200 but missing anchor)
- (903:168) 'https://..' => https://github.com/npm/node-semver#usage (HTTP 200 but missing anchor)
- (911:25) 'Array.sort' => https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#Description (HTTP 200 but missing anchor)
- (957:25) 'https://..' => https://github.com/npm/node-semver#usage (HTTP 200 but missing anchor)


Stats:
  125123 links
    1295 destination URLs
       1 URLs ignored
       8 warnings
       8 errors

[ghost]

Hello @scottn12!

Because this pull request has the msftbot: merge-next label, I will be glad to assist with helping to merge this pull request once all check-in policies pass.

p.s. you can customize the way I help with merging this pull request, such as holding this pull request until a specific person approves. Simply @mention me (@msftbot) and give me an instruction to get started! Learn more here.