tree: Import / Export APIs and demo

[CraigMacomber]

Description

Added import/export options for tree content and schema, and example script using them.

Reviewer Guidance

The review process is outlined on this wiki page.

[msfluid-bot]

Code Coverage Summary

↓ packages.dds.tree.src.shared-tree:
Line Coverage Change: -0.23%    Branch Coverage Change: -0.57%

Metric Name	Baseline coverage	PR coverage	Coverage Diff
Branch Coverage	91.34%	90.77%	↓ -0.57%
Line Coverage	97.42%	97.19%	↓ -0.23%

↑ packages.dds.tree.src.codec:
Line Coverage Change: 0.02%    Branch Coverage Change: 0.10%

Metric Name	Baseline coverage	PR coverage	Coverage Diff
Branch Coverage	95.55%	95.65%	↑ 0.10%
Line Coverage	99.60%	99.62%	↑ 0.02%

↑ packages.dds.tree.src.feature-libraries.flex-tree:
Line Coverage Change: 0.09%    Branch Coverage Change: 0.05%

Metric Name	Baseline coverage	PR coverage	Coverage Diff
Branch Coverage	93.37%	93.42%	↑ 0.05%
Line Coverage	89.97%	90.06%	↑ 0.09%

↑ packages.dds.tree.src.simple-tree.api:
Line Coverage Change: -0.04%    Branch Coverage Change: 1.36%

Metric Name	Baseline coverage	PR coverage	Coverage Diff
Branch Coverage	86.49%	87.85%	↑ 1.36%
Line Coverage	81.75%	81.71%	↓ -0.04%

---

Baseline commit: 522f76f
Baseline build: 303346
Happy Coding!!

Code coverage comparison check passed!!

[jzaffiro]

A few minor comments, but docs look good!

[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

> [email protected] ci:linkcheck /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test ci:start 1313 linkcheck:full

1: starting server using command "npm run ci:start"
and when url "[ 'http://127.0.0.1:1313' ]" is responding with HTTP status code 200
running tests using command "npm run linkcheck:full"


> [email protected] ci:start
> http-server ./public --port 1313 --silent


> [email protected] linkcheck:full
> npm run linkcheck:fast -- --external


> [email protected] linkcheck:fast
> linkcheck http://localhost:1313 --skip-file skipped-urls.txt --external

Crawling...

Stats:
  440694 links
    3397 destination URLs
       2 URLs ignored
       0 warnings
       0 errors