[User story] User feedback

[alexkisielewicz]

As a user, I want to receive feedback as a response to my actions, so that I can have a clear understanding of the outcome of my actions and stay informed.

Acceptance Criteria:

• Feedback messages are displayed in the form of a toast UI component that disappears automatically after a short time.
• Appropriate message is displayed on such occasions as sign-in/out, creation of an account, adding a post, editing a post, adding or deleting the comment, editing profile details, username, or password.
• The confirmation toast message is shown to the user only when the action performed results in a successful change in the database.