Auto play consecutive audio messages, prefetch audio messages, show fetched audio durations, temporarily mark as listened audio messages, fixed a bug to listen last second of audio message

[Ruggero1912]

🖼️ Screenshots

🏚️ Before	🏡 After
B	A
YT demo before changes	YT demo after changes

🏁 Checklist

• ⛑️ Tests (unit and/or integration) are included or not needed
• 🔖 Capability is checked or not needed
• 🔙 Backport requests are created or not needed: /backport to stable-xx.x
• 📅 Milestone is set
• 🌸 PR title is meaningful (if it should be in the changelog: is it meaningful to users?)

Changes

• prefetch audio messages, show fetched audio durations: when an audio is played, the former and latter 5 messages are fetched from the server if are not present locally, and their duration is computed and shown.
• temporarily mark as listened audio messages: when the mediaplayer position is after the 5% of the voice message duration, set a boolean in ChatMessage class wasPlayedVoiceMessage, the background color of the voice message bubble is updated.
• fixed a bug to listen last second of audio message: pos = mediaPlayer!!.currentPosition / VOICE_MESSAGE_SEEKBAR_BASE in the runnable of the mediaPlayerHandler defined in startPlayback method of ChatActivity was an integer before, and the check pos < (mediaPlayer!!.duration / VOICE_MESSAGE_SEEKBAR_BASE) returned false in cases such as currentPosition was 9.1 seconds and mediaPlayer.duration was 9.9 seconds. This led to not playing the last part of voice messages.
• Auto play consecutive audio messages: if the played voice message has a consecutive voice message, it will be played after the current one