added contributing details

[paullizer]

No description provided.

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds contributor guidance to both the documentation site and repository root, and updates a few dependencies.

Changes:

• Add “Contributing” sections/links to README and docs landing page, plus a new contributing guide page in docs and root.
• Add Contributing nav entry in the docs site config.
• Update dependencies (Ruby addressable override for docs site; Python requests version bumps for external tools).

Reviewed changes

Copilot reviewed 8 out of 9 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
docs/index.md	Adds a Contributing section/link to the docs landing page.
docs/contributing.md	Introduces a docs-site Contributing guide with workflow and local dev instructions.
docs/_config.yml	Adds “Contributing” to the docs navigation menu.
docs/Gemfile.lock	Updates addressable resolution and adds it to explicit dependencies in lock.
docs/Gemfile	Pins/overrides addressable version for security.
application/external_apps/databaseseeder/requirements.txt	Bumps requests version.
application/external_apps/bulkloader/requirements.txt	Bumps requests version.
README.md	Adds a Contributing section linking to root CONTRIBUTING.md.
CONTRIBUTING.md	Adds a root contribution guide.