feat: upload docs to the dfinity/icp-js-sdk-docs repo

[ilbertt]

Description

Adds a job to the publish.yml workflow to zip the docs, push them to the icp-pages branch and trigger the workflow on the dfinity/icp-js-sdk-docs repo.

Depends on:

• feat: extract version action ci-tools#45
• feat: assemble-docs action ci-tools#46
• feat: submit-docs action ci-tools#47
• refactor: move upgrading guide to v4 path #1107

Additionally, this PR:

• adds the versions dropdown on the docs sidebar as a plugin
• moves the release-notes/v300 page to upgrading/v3

How Has This Been Tested?

A temporary action was created while this PR was open. That action has been removed before merging and its step copied to the publish.yml's publish-docs job.

Checklist:

• My changes follow the guidelines in CONTRIBUTING.md.
• The title of this PR complies with Conventional Commits.
• I have edited the CHANGELOG accordingly.
• I have made corresponding changes to the documentation.

[github-actions]

size-limit report 📦

Path	Size
@dfinity/agent	50.37 KB (0%)
@dfinity/assets	55.38 KB (0%)
@dfinity/auth-client	21.15 KB (0%)
@dfinity/candid	13.22 KB (0%)
@icp-sdk/core	91 B (0%)
@dfinity/identity	20.59 KB (0%)
@dfinity/identity-secp256k1	33.88 KB (0%)
@dfinity/principal	4.44 KB (0%)
@dfinity/use-auth-client	61.27 KB (0%)