feat: add a syncing job with docs

[AstraBert]

This PR adds a script (scripts/sync_landing_docs.py) which:

• Recursively goes through the docs/reference folder
• Reads each file and applies the required modifications (tagging code blocks, making sure we only have one H1 title, replacing relative links with global links suitable for the landing_page docs)
• Writes each file to the destination, i.e. qdrant-landing/content/documentation/cloud-cli/ (the old Cloud CLI page is preserved as section overview under _index.md)

Syncing with the landing_page repo happens on release, and goes through the following steps:

• Running docs generation
• Checking out the qdrant/landing_page repo
• Running the syncing scripts between the two local repos
• Adding and committing changes
• Checking out a dedicated branch, pushing changes to it
• Opening a PR in the landing_page repo

The workflow just needs a PAT that has write access to PRs for qdrant/landing_page

[AstraBert]

Closing this one. Opening follow-up PR soon migrating this to golang as discussed off-GitHub