[WIP][NEW] Group same user messages

[Adizbek]

@RocketChat/android

Closes #712
As describe in issue:

Group messages:

Take in consideration the setting (Message_GroupingPeriod -> default is 900 seconds);
When there's a day separator, can't be sequential;
When a message is a system message (message removed, pinned message, permission changes, etc)
Users need to be the same in order to group it;

Some criteria not implemented yet.

Screenshots or GIF for the change:

https://youtu.be/3ciV8ZmTaE0

[Adizbek]

@filipedelimabrito I have fixed all issues which you listed above.

[jungeonkim]

Is not it good to consider it when the alias is different?

RocketChat/Rocket.Chat.iOS#2684

[Adizbek]

@jungeonkim Yes, you're right. I have fixed. Now code looks better.

[philipbrito]

@Adizbek Is it still a WIP?

[Adizbek]

@filipedelimabrito The only last part remained, As said in issue #712

Message_GroupingPeriod -> default is 900 seconds

I couldn't find how to realize it, currently it is manually set to 900sec.

[peterkogit]

Something all stopped