Fold in MD in write-ups into docs

[wenrizc]

This pull request resolves issue https://github.com/apache/hamilton/issues/1389 by integrating the content from the /writeups directory into /docs directory.

move the markdown files under hamilton/tree/main/writeups to hamilton/tree/main/docs

Changes

Content Migration: The informational content from various Markdown files within the /writeups directory has been moved to the /docs directory. developer_setup.md -> docs/community data_quality.md -> docs/concepts decorators.md-> docs/concepts /garbage_collection-> docs/concepts basics.md-> docs/get-started Directory Removal: The /writeups directory and its contents have been deleted, as they are now redundant.

[skrawcz]

Docs build fails with :

/home/runner/work/hamilton/hamilton/docs/community/developer_setup.md:74: WARNING: 'myst' cross-reference target not found: 'how-to-run-unit-tests' [myst.xref_missing]
/home/runner/work/hamilton/hamilton/docs/concepts/decorators.md:3: WARNING: 'myst' cross-reference target not found: 'hamilton/function_modifiers.py' [myst.xref_missing]
/home/runner/work/hamilton/hamilton/docs/concepts/decorators.md:422: WARNING: 'myst' cross-reference target not found: 'examples/reusing_functions/reusable_subdags.py' [myst.xref_missing]
/home/runner/work/hamilton/hamilton/docs/concepts/garbage_collection/post.md:13: WARNING: 'myst' cross-reference target not found: 'www.tryhamilton.dev' [myst.xref_missing]
/home/runner/work/hamilton/hamilton/docs/get-started/basics.md:90: WARNING: 'myst' cross-reference target not found: '/hamilton/driver.py' [myst.xref_missing]

You can build them locally with https://github.com/apache/hamilton/blob/14143a504166fc10e9eac269fc377536ab36c2e5/docs/README.md