feat(pages): display pages from ghost (eg. : about page and accessibility page)

src/app/about/about.component.html

src/app/about/about.component.ts

src/app/app-routing.module.ts

src/app/app.module.ts

src/app/footer/footer.component.html

src/app/header/header.component.html

src/app/page/enum/page.enum.ts

src/app/page/models/page.model.ts

src/app/page/page.component.html

src/app/page/page.component.scss

src/app/page/page.component.spec.ts

src/app/page/page.component.ts

src/app/page/services/page.service.spec.ts

src/app/page/services/page.service.ts

.../post/components/post-details/post-details.component.scss

src/assets/scss/_ghost.scss

src/sitemap.xml