Build script improvements

[gingerwizard]

ClickHouse/ClickHouse repo is currently using build in its DocsCheck. This will fail once we enabled docusaurus v3 link checker - as the auto generated settings pages will be missing. It could use new-build (like Vercel) but this has issues (see below)

Our build scripts are alittle disjointed and inconsistent. We have both new-build and build. new-build includes settings generation. build was kept (we believe) so people could do local builds. We need to consolidate. Possible approach:

• new-build uses copyClickhouseRepoDocs but this clones the ClickHouse repo to copy the reference docs. new-build could accept a path, passing this to copyClickhouseRepoDocs - this could then use prep-from-local.
• settings generation will need to be its own yarn action - as people will need to do this locally for links to not break. This needs the latest of clickhouse - so it pulls it from a binary. Update docs.
• prep-from-local should only copy changed files. Maybe we use rsync if installed, otherwise default to current implementation.

Move scripts to single directory and add linter for python and bash.