Docs: Add <Form> reference page

[delbaoliveira]

Document new next/form API.
Related: #68102

DOC-3112

[github-actions]

All broken links are now fixed, thank you!

[Netail]

Regarding the whole next/form package, will it also include a way to prevent CSRF attacks? e.g. with csrf token handling

[delbaoliveira]

Waiting for: #68340

[leerob]

@Netail https://nextjs.org/blog/security-nextjs-server-components-actions#csrf

[Netail]

@Netail https://nextjs.org/blog/security-nextjs-server-components-actions#csrf

Yup, server actions are fine, was more wondering regarding route handlers

When Custom Route Handlers (route.tsx) are used instead, extra auditing can be necessary since CSRF protection has to be done manually there. The traditional rules apply there.