Add legacy tags to the added apis for creating and loading container

[jatgarg]

Description

Add legacy tags to the added apis for creating and loading container. Earlier these apis only had the alpha tag which is not correct as Loop would not consume the alpha apis in prod code and also these depends on legacy things as well. So these apis could not just be alpha.

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[github-actions]

🔗 No broken links found! ✅

Your attention to detail is admirable.

linkcheck output

> fluid-framework-docs-site@0.0.0 ci:check-links /home/runner/work/FluidFramework/FluidFramework/docs
> start-server-and-test "npm run serve -- --no-open" 3000 check-links

1: starting server using command "npm run serve -- --no-open"
and when url "[ 'http://127.0.0.1:3000' ]" is responding with HTTP status code 200
running tests using command "npm run check-links"


> fluid-framework-docs-site@0.0.0 serve
> docusaurus serve --no-open

[SUCCESS] Serving "build" directory at: http://localhost:3000/

> fluid-framework-docs-site@0.0.0 check-links
> linkcheck http://localhost:3000 --skip-file skipped-urls.txt

Crawling...

Stats:
  170006 links
    1595 destination URLs
    1825 URLs ignored
       0 warnings
       0 errors