Add integration with Jellyseerr/Seerr (#558)

## Description
This PR add the ability to integrate with a [Jellyseerr/Seerr
server](https://github.com/seerr-team/seerr).

### Features
- Login to the Seerr server using API Key, Jellyfin credentials, or
local Seerr credentials
    - Separate Seerr logins per user profile
- Search Seerr from the search page
- Discover media from Seerr on the nav drawer `Discover` page
    - Also from movie, series, or person pages
- Seamless integration with existing media, i.e. selecting media found
from Seerr that already exists on the Jellyfin server, will go directly
to the regular media page
- Mostly consistent UI between Jellyfin media & Seerr media
- Submit requests to Seerr
- Cancel submitted requests

### Screenshots

![discover](https://github.com/user-attachments/assets/f830b48f-e2f1-43f4-9680-9c6d4e071765)

### Related issues
Closes #54

## Acknowledgements

The `app/src/main/seerr/seerr-api.yml` file is copied & modified from
https://github.com/seerr-team/seerr/blob/develop/seerr-api.yml. I hope
to try to upstream some of the changes in the future.

app/src/main/res/values/strings.xml

@@ -253,6 +253,22 @@
         <item quantity="other">%d seconds</item>
     </plurals>
 
+    <plurals name="movies">
+        <item quantity="zero">Movies</item>
+        <item quantity="one">Movie</item>
+        <item quantity="other">Movies</item>
+    </plurals>
+    <plurals name="tv_shows">
+        <item quantity="zero">TV Shows</item>
+        <item quantity="one">TV Show</item>
+        <item quantity="other">TV Shows</item>
+    </plurals>
+    <plurals name="people">
+        <item quantity="zero">People</item>
+        <item quantity="one">Person</item>
+        <item quantity="other">People</item>
+    </plurals>
+
     <!-- Preferences/Setting specific strings -->
     <string name="pref_key_update_last_check_threshold" translatable="false">preference.update.threshold</string>
     <string name="pref_key_update_last_check" translatable="false">preference.update.lastTimestamp</string>
@@ -413,6 +429,18 @@
     <string name="force_dovi_profile_7">Direct play Dolby Vision Profile 7</string>
     <string name="force_dovi_profile_7_summary">Ignores device compatibility checks</string>
 
+    <string name="discover">Discover</string>
+    <string name="request">Request</string>
+    <string name="pending">Pending</string>
+    <string name="seerr_integration">Seerr integration</string>
+    <string name="remove_seerr_server">Remove Seerr Server</string>
+    <string name="password">Password</string>
+    <string name="username">Username</string>
+    <string name="url">URL</string>
+    <string name="trending">Trending</string>
+    <string name="upcoming_movies">Upcoming Movies</string>
+    <string name="upcoming_tv">Upcoming TV Shows</string>
+
     <string-array name="theme_song_volume">
         <item>Disabled</item>
         <item>Lowest</item>