Add Javascript API versioning

[vi-nastya]

This PR adds setup for versioning javascript api section

Deployed: https://mdr-ci.staging.k6.io/docs/refs/pull/283/merge/javascript-api/

How it works
Currently we only support versioning for Javascript API section of the docs.
Files for the latest version are located in src/data/markdown/docs/02 javascript api and page URLs have no version prefix.

Other versions are located in src/data/markdown/versioned-js-api and URLs for versioned pages contain the version number (e.g. https://k6.io/docs/javascript-api/v0-31/,https://k6.io/docs/javascript-api/v0-31/k6-crypto/createhash-algorithm/)

How to add a new version
Let's say the v0.33 is released and we want to add docs for it and make it the new latest version.

1. Run npm run archive-version v0.32 (you might need to run chmode +x ./archive-js-api-version.sh first)
   This script will create a new folder inside src/data/markdown/versioned-js-api named v0.32 and copy the content of src/data/markdown/docs/02 javascript api there.
   It would also replace internal links in md files for javascript api section to point to v0.32 pages.
   If any pages had a custom slug set in the frontmatter, the value would also be updated to include version number

2. Go to src/utils/versioning.js and add v0.32 to SUPPORTED_VERSIONS. Set LATEST_VERSION = v0.33.

3. Add docs for v0.33 to src/data/markdown/docs/02 javascript api

Screenshot

[github-actions]

There's a version of the docs published here:

https://mdr-ci.staging.k6.io/docs/refs/pull/283/merge

It will be deleted automatically in 30 days.

[ppcano]

@vi-nastya Please, can you rebase master and fix the conflicts. Then, I will do the final testing.

I'd like to launch with:

• latest/0.32 -> available in master branch.
• v.0.31 -> which is previous to 0b7459c

[vi-nastya]

@ppcano the master is already merged into this branch and the conflicts are resolved. Would you like me to add the correct file versions for v.0.31 and v.0.32?