Add PostgreSQL support to the bot stack

[obervinov]

DB Tables:
queue: messages received by the bot are placed in this table for further processing at the specified time by a separate thread

• id (int)
• user id (int)
• post url (str)
• post id (str)
• scheduled_time (datetime)
• timestamp (datetime)
• post owner (str)
• message id (str)
• chat id (str)
• link type (post or profile) (str)
• state (str)

processed: historical data from vault should be migrated here and after processing from queue, the record should be moved to this table, enriched with additional data

• id (int)
• queue id (str)
• user id (str)
• post url (str)
• post id (str)
• timestamp (datetime)
• download status (str)
• upload status (str)
• post owner (str)

migrations: table for service migrations (for example, transferring historical data from vault)

• id (str)
• name (str)
• version (str)
• completion time (datetime)

To-Do:

• Write migration of historical data from vault to postgresql
  • migration should leave a mark in the migrations table after completion
  • the migration shouldn’t delete the migrated data in the vault
• The bot should automatically create tables in the database at startup
• The configuration of the database connection must be stored and read by the vault
• To work with a database, you need to create a separate class with a set of methods and attributes for interacting with tables