Add errorService, handling errors in editorialisation module

src/app/core/core.module.ts

src/app/core/handlers/errors-handler.ts

src/app/core/interceptors/http-error-response-interceptor.ts

src/app/core/services/error.service.ts

src/app/core/services/index.ts

src/app/editorialisation/components/home/home.component.html

src/app/editorialisation/components/home/home.component.scss

src/app/editorialisation/components/home/home.component.ts

src/app/editorialisation/components/index.ts

.../wordpress-page-error/wordpress-page-error.component.html

.../wordpress-page-error/wordpress-page-error.component.scss

...rdpress-page-error/wordpress-page-error.component.spec.ts

...ts/wordpress-page-error/wordpress-page-error.component.ts

...n/components/wordpress-page/wordpress-page.component.html

...ion/components/wordpress-page/wordpress-page.component.ts

.../wordpress-posts-list/wordpress-posts-list.component.html

src/app/editorialisation/resolvers/page.resolver.ts

src/app/editorialisation/resolvers/post-detail.resolver.ts

src/app/editorialisation/resolvers/post-video.resolver.ts

src/app/editorialisation/resolvers/posts-list.resolver.ts