Add Lighthouse metrics documentation (#9379)
Add Lighthouse metrics documentation (#9379)

* Add lighthouse metrics documentation

* Amend text for consistency

Co-authored-by: Antti Hukkanen <1cf288b80902fb246320ae2ee16ddf564b78626e@mainiotech.fi>

Co-authored-by: Antti Hukkanen <1cf288b80902fb246320ae2ee16ddf564b78626e@mainiotech.fi>
decidim/decidim,decidim/decidim,decidim/decidim