feat: Option on item's page to add/remove from watchlist (#781)

* feat: adds button on the page of a media item to add or remove it from a user's watchlist

re #730

* fix: whitespace and i18n key

* style: fix code format to the required standards

* refactor: change axios for the fetch api

---------

Co-authored-by: JoaquinOlivero <joaquin.olivero@hotmail.com>

server/models/Tv.ts

@@ -111,6 +111,7 @@ export interface TvDetails {
   keywords: Keyword[];
   mediaInfo?: Media;
   watchProviders?: WatchProviders[];
+  onUserWatchlist?: boolean;
 }
 
 const mapEpisodeResult = (episode: TmdbTvEpisodeResult): Episode => ({
@@ -161,7 +162,8 @@ export const mapNetwork = (network: TmdbNetwork): TvNetwork => ({
 
 export const mapTvDetails = (
   show: TmdbTvDetails,
-  media?: Media
+  media?: Media,
+  userWatchlist?: boolean
 ): TvDetails => ({
   createdBy: show.created_by,
   episodeRunTime: show.episode_run_time,
@@ -223,4 +225,5 @@ export const mapTvDetails = (
   })),
   mediaInfo: media,
   watchProviders: mapWatchProviders(show['watch/providers']?.results ?? {}),
+  onUserWatchlist: userWatchlist,
 });