Separate out prep-from-local, prep-from-master commands into .sh files

[Blargian]

Summary

prep-from-local and prep-from-master commands are difficult to modify or maintain if needed in their current form.
This PR separates out those commands into their own .sh files, adds comments and some basic error handling.

Checklist

• Delete items not relevant to your PR
• URL changes should add a redirect to the old URL via https://github.com/ClickHouse/clickhouse-docs/blob/main/docusaurus.config.js
• If adding a new integration page, also add an entry to the integrations list here: https://github.com/ClickHouse/clickhouse-docs/blob/main/docs/en/integrations/index.mdx

[gingerwizard]

@Blargian i want to rework this completely, lets discuss.

[Blargian]

@gingerwizard I'm going to work on build script improvements today, but would like to merge this first #2951 (separates out the prep-from-local and prep-from-master scripts to their own files)

Let's improve incrementally

[gingerwizard]

@Blargian lets merge this, can you fix the package.json - exclude it from the PR not related