feat: documentation site (#1101)

## Description

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## Related Issue

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## Changes Made

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- Change 1
- Change 2
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## Testing Performed

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## Checklist

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- [ ] I have tested these changes locally and they work as expected.
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- [ ] I have updated the documentation to reflect these changes, if
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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **Documentation**
- Enhanced project README for clarity and improved environment variables
section.
- Added comprehensive developer and user documentation, including guides
on local development, public API, self-hosting, and compliance
standards.
- Introduced specific guides for contributing, creating API keys, using
webhooks, and setting up security measures.
- Detailed documentation on various fields available for document
signing to improve user understanding.
- Added metadata structuring to improve navigation within the
documentation site.

- **Chores**
  - Updated `.gitignore` to better handle project files.

- **New Features**
- Introduced detailed metadata and documentation for various Documenso
functionalities, including signing documents, user profiles, and
compliance levels.
- Added functionality for Direct Link Signing, enabling easy sharing for
document signing.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Timur Ercan <timur.ercan31@gmail.com>
Co-authored-by: Lucas Smith <me@lucasjamessmith.me>
Co-authored-by: David Nguyen <davidngu28@gmail.com>

package.json

@@ -4,8 +4,8 @@
   "scripts": {
     "build": "turbo run build",
     "build:web": "turbo run build --filter=@documenso/web",
-    "dev": "turbo run dev --filter=@documenso/web --filter=@documenso/marketing",
-    "start": "turbo run start --filter=@documenso/web --filter=@documenso/marketing",
+    "dev": "turbo run dev --filter=@documenso/web --filter=@documenso/marketing --filter=@documenso/documentation",
+    "start": "turbo run start --filter=@documenso/web --filter=@documenso/marketing --filter=@documenso/documentation",
     "lint": "turbo run lint",
     "lint:fix": "turbo run lint:fix",
     "format": "prettier --write \"**/*.{js,jsx,cjs,mjs,ts,tsx,cts,mts,mdx}\"",