Implement MSC2530 (#2570)

* Implement MSC2530
* Some layout improvements for images and videos with captions
* Update screenshots
* Replace `it` in several previews with `isMine`

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Signed-off-by: Marco Antonio Alvarez <surakin@gmail.com>
Co-authored-by: Marco Antonio Alvarez <surakin@gmail.com>
Co-authored-by: ElementBot <benoitm+elementbot@element.io>

libraries/matrix/api/src/main/kotlin/io/element/android/libraries/matrix/api/timeline/item/event/MessageType.kt

@@ -34,6 +34,8 @@ data class EmoteMessageType(
 
 data class ImageMessageType(
     val body: String,
+    val formatted: FormattedBody?,
+    val filename: String?,
     val source: MediaSource,
     val info: ImageInfo?
 ) : MessageType
@@ -65,6 +67,8 @@ data class VoiceMessageType(
 
 data class VideoMessageType(
     val body: String,
+    val formatted: FormattedBody?,
+    val filename: String?,
     val source: MediaSource,
     val info: VideoInfo?
 ) : MessageType