Improve SEO

[julienbrg]

• Fix next.config.js
• Add <NextSeo> tag in every pages + proposal description

<NextSeo
        title="Gov"
        description="DAOs for everyday people"
        titleTemplate={`%s`}
        // description={SITE_DESCRIPTION}
        // defaultOpenGraphImageWidth={1200}
        // defaultOpenGraphImageHeight={630}
        openGraph={{
          type: 'website',
          siteName: SITE_NAME,
          url: origin,
          images: [
            {
              url: `${origin}/huangshan.png`,
              width: 1200,
              height: 630,
              alt: 'Huangshan',
            },
          ],
        }}
      />

https://github.com/w3hc/gov-ui/blob/main/src/pages/index.tsx#L231C7-L251C9

https://socialsharepreview.com/
https://www.opengraph.xyz/

[julienbrg]

Also fix this: https://socialsharepreview.com/?url=https://gov-ui.netlify.app/