Custom Facebook metatags for organizations

[magul]

In #1056 we introduced default Facebook metatags, that will be set for every router change. For offer components we should introduce custom metatags (seting them inside ngOnInit)

{ name: 'og:title', content: `${organization.name} - Volontulo. Portal dla wolontariuszy` }
{ name: 'og:description', content: organization.description }

[dianawieczorek]

#1069