Populate DB improvements / fixes

[churik]

Problem

Script to populate db is extremely useful in terms of client performance testing, however currently it is working with some issues and it would be nice to have more possibilities to use it.

ISSUES

Tested with feature/resize-images branch.

./populate-db --one-to-one-chats 1 --number-of-messages 100000 --seed-phrase "clog beach hour copper wolf buddy census gas dance tattoo wash laptop" produces 5 public chats and 1 one-to-one chat and 200 contacts

• ISSUE1: can't see messages in 1-1 chat
• ISSUE2: can scroll ~1500 messages up for public chats, everything which is under is shown with an endless spinner

FILE_2022-06-06_124758.mp4

Expected behavior:
can scroll to the start of the chat history and read all messages

DESIRED FEATURES

Would be nice to have the ability to produce different message types:

• audio
• stickers
• images
• text with markdown

If talking about performance I'm not sure is there a difference between communities and public chats.
If yes, it is crucial to have the ability to generate communities with different types of messages.

[churik]

cc @cammellos