rn: add ability to set the conference subject

android/sdk/src/main/java/org/jitsi/meet/sdk/JitsiMeetConferenceOptions.java

      * Room name.
      */
     private String room;
+    /**
+     * Conference subject.
+     */
+    private String subject;
     /**
      * JWT token used for authentication.
      */
     public static class Builder {
         private URL serverURL;
         private String room;
+        private String subject;
         private String token;
 
         private Bundle colorScheme;
             return this;
         }
 
+        /**
+         * Sets the conference subject.
+         * @param subject - Subject for the conference.
+         * @return - The {@link Builder} object itself so the method calls can be chained.
+         */
+        public Builder setSubject(String subject) {
+            this.subject = subject;
+
+            return this;
+        }
+
         /**
          * Sets the JWT token to be used for authentication when joining a conference.
          * @param token - The JWT token to be used for authentication.
 
             options.serverURL = this.serverURL;
             options.room = this.room;
+            options.subject = this.subject;
             options.token = this.token;
             options.colorScheme = this.colorScheme;
             options.audioMuted = this.audioMuted;
 
     private JitsiMeetConferenceOptions(Parcel in) {
         room = in.readString();
+        subject = in.readString();
         token = in.readString();
         colorScheme = in.readBundle();
         byte tmpAudioMuted = in.readByte();
         if (videoMuted != null) {
             config.putBoolean("startWithVideoMuted", videoMuted);
         }
+        if (subject != null) {
+            config.putString("subject", subject);
+        }
 
         Bundle urlProps = new Bundle();
 
     @Override
     public void writeToParcel(Parcel dest, int flags) {
         dest.writeString(room);
+        dest.writeString(subject);
         dest.writeString(token);
         dest.writeBundle(colorScheme);
         dest.writeByte((byte) (audioMuted == null ? 0 : audioMuted ? 1 : 2));

ios/sdk/src/JitsiMeetConferenceOptions.h

  * Room name.
  */
 @property (nonatomic, copy, nullable) NSString *room;
+/**
+ * Conference subject.
+ */
+@property (nonatomic, copy, nullable) NSString *subject;
 /**
  * JWT token used for authentication.
  */
 @interface JitsiMeetConferenceOptions : NSObject
 
 @property (nonatomic, copy, nullable, readonly) NSURL *serverURL;
+
 @property (nonatomic, copy, nullable, readonly) NSString *room;
+@property (nonatomic, copy, nullable, readonly) NSString *subject;
 @property (nonatomic, copy, nullable, readonly) NSString *token;
 
 @property (nonatomic, copy, nullable) NSDictionary *colorScheme;

ios/sdk/src/JitsiMeetConferenceOptions.m

     if (self = [super init]) {
         _serverURL = nil;
         _room = nil;
+        _subject = nil;
         _token = nil;
 
         _colorScheme = nil;
     if (self = [super init]) {
         _serverURL = builder.serverURL;
         _room = builder.room;
+        _subject = builder.subject;
         _token = builder.token;
 
         _colorScheme = builder.colorScheme;
     if (_videoMuted != nil) {
         config[@"startWithVideoMuted"] = @(self.videoMuted);
     }
+    if (_subject != nil) {
+        config[@"subject"] = self.subject;
+    }
 
     NSMutableDictionary *urlProps = [[NSMutableDictionary alloc] init];