Room screen: timeline message bubbles (#91)

* #34 Create `TimelineItemStylerView`

* #34 Add styler view into different type of cells

* #34 Use placeholder avatar image on room list

* #34 Add `isOutgoing` param to event based timeline item

* #34 Compute `isOutgoing` for timeline items

* #34 Update sender info view in timeline

* #34 Update mock timeline items

* #34 Rename `EventBasedTimelineView` to `EventBasedTimelineSenderView`

* #34 Change padding on timeline cells

* #34 Create `TimelineItemStylerView` to move content into a bubble if needed

* #34 Use styler view in all of the timeline item views

* #34 Make timestamp more readable on images

* #34 Little layout tweaks

* #34 Add changelog

* #34 Fix code smells

* #34 Set text colors on timeline items

* #34 Fix background color of the timeline

* #34 Fix PR remarks

* #34 Set background colors explicitly on remaining screens

* #34 Reduce min bubble width and make it a scaled metric

* #34 Refactor `PlaceholderAvatarImage` to accept a text only

* #34 Fix code smell

* #34 Fix further comments

ElementX/Sources/Services/Timeline/TimelineItems/Items/EmoteRoomTimelineItem.swift

@@ -15,6 +15,7 @@ struct EmoteRoomTimelineItem: EventBasedTimelineItemProtocol, Identifiable, Equa
     var attributedComponents: [AttributedStringBuilderComponent]?
     let timestamp: String
     let shouldShowSenderDetails: Bool
+    let isOutgoing: Bool
     
     let senderId: String
     var senderDisplayName: String?

ElementX/Sources/Services/Timeline/TimelineItems/Items/ImageRoomTimelineItem.swift

@@ -14,6 +14,7 @@ struct ImageRoomTimelineItem: EventBasedTimelineItemProtocol, Identifiable, Equa
     let text: String
     let timestamp: String
     let shouldShowSenderDetails: Bool
+    let isOutgoing: Bool
     
     let senderId: String
     var senderDisplayName: String?

ElementX/Sources/Services/Timeline/TimelineItems/Items/NoticeRoomTimelineItem.swift

@@ -15,6 +15,7 @@ struct NoticeRoomTimelineItem: EventBasedTimelineItemProtocol, Identifiable, Equ
     var attributedComponents: [AttributedStringBuilderComponent]?
     let timestamp: String
     let shouldShowSenderDetails: Bool
+    let isOutgoing: Bool
     
     let senderId: String
     var senderDisplayName: String?

ElementX/Sources/Services/Timeline/TimelineItems/Items/TextRoomTimelineItem.swift

@@ -15,6 +15,7 @@ struct TextRoomTimelineItem: EventBasedTimelineItemProtocol, Identifiable, Equat
     var attributedComponents: [AttributedStringBuilderComponent]?
     let timestamp: String
     let shouldShowSenderDetails: Bool
+    let isOutgoing: Bool
     
     let senderId: String
     var senderDisplayName: String?