Displayed the date of each announcement. (#4041)

## Issue
Close #3967 

# What I did
- Displayed the date of each announcement.
  - Date is placed in the lower left corner of the Announcement
- Supported date format internationalization using
getBestDateTimePattern

# Screenshot
<image
src="https://github.com/tuskyapp/Tusky/assets/62137820/7c124183-1a13-4cae-8667-ff82ca99b60c"
width="500"/>

## Note
I am not good at English so I use machine translation a bit. So, you may
find my writing style a little strange...

app/src/main/java/com/keylesspalace/tusky/components/announcements/AnnouncementAdapter.kt

@@ -30,6 +30,7 @@ import com.keylesspalace.tusky.R
 import com.keylesspalace.tusky.databinding.ItemAnnouncementBinding
 import com.keylesspalace.tusky.entity.Announcement
 import com.keylesspalace.tusky.interfaces.LinkListener
+import com.keylesspalace.tusky.util.AbsoluteTimeFormatter
 import com.keylesspalace.tusky.util.BindingHolder
 import com.keylesspalace.tusky.util.EmojiSpan
 import com.keylesspalace.tusky.util.emojify
@@ -51,6 +52,8 @@ class AnnouncementAdapter(
     private val animateEmojis: Boolean = false
 ) : RecyclerView.Adapter<BindingHolder<ItemAnnouncementBinding>>() {
 
+    private val absoluteTimeFormatter = AbsoluteTimeFormatter()
+
     override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): BindingHolder<ItemAnnouncementBinding> {
         val binding = ItemAnnouncementBinding.inflate(LayoutInflater.from(parent.context), parent, false)
         return BindingHolder(binding)
@@ -60,6 +63,8 @@ class AnnouncementAdapter(
     override fun onBindViewHolder(holder: BindingHolder<ItemAnnouncementBinding>, position: Int) {
         val item = items[position]
 
+        holder.binding.announcementDate.text = absoluteTimeFormatter.format(item.publishedAt, false)
+
         val text = holder.binding.text
         val chips = holder.binding.chipGroup
         val addReactionChip = holder.binding.addReactionChip

app/src/main/res/layout/item_announcement.xml

@@ -22,7 +22,8 @@
         android:padding="8dp"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
-        app:layout_constraintTop_toBottomOf="@id/text">
+        app:layout_constraintTop_toBottomOf="@id/text"
+        app:layout_constraintBottom_toTopOf="@id/announcementDate">
 
         <com.google.android.material.chip.Chip
             android:id="@+id/addReactionChip"
@@ -39,4 +40,16 @@
 
     </com.google.android.material.chip.ChipGroup>
 
+    <TextView
+        android:id="@+id/announcementDate"
+        android:layout_width="0dp"
+        android:layout_height="wrap_content"
+        android:paddingHorizontal="8dp"
+        android:paddingBottom="8dp"
+        android:lineSpacingMultiplier="1.1"
+        app:layout_constraintEnd_toEndOf="parent"
+        app:layout_constraintStart_toStartOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/chipGroup"
+        />
+
 </androidx.constraintlayout.widget.ConstraintLayout>