Implement month separator for the Gallery.

Improve day separator rendering in the timeline.
Use Today, Yesterday, and the name of the day if less than 7 days and do not render the year for the current year.
Improve date format for the media viewer.
Rework how date and time are computed.
ActionListView: Time can take more space, so update the layout.

libraries/core/src/main/kotlin/io/element/android/libraries/core/extensions/BasicExtensions.kt

@@ -7,6 +7,8 @@
 
 package io.element.android.libraries.core.extensions
 
+import java.util.Locale
+
 fun Boolean.toOnOff() = if (this) "ON" else "OFF"
 fun Boolean.to01() = if (this) "1" else "0"
 
@@ -68,3 +70,16 @@ fun String.replacePrefix(oldPrefix: String, newPrefix: String): String {
 fun String.withBrackets(prefix: String = "(", suffix: String = ")"): String {
     return "$prefix$this$suffix"
 }
+
+/**
+ * Capitalize the string.
+ */
+fun String.safeCapitalize(): String {
+    return replaceFirstChar {
+        if (it.isLowerCase()) {
+            it.titlecase(Locale.getDefault())
+        } else {
+            it.toString()
+        }
+    }
+}