User profile: Public and customiseable user profiles

[josecelano]

Parent: #649

Create a public profile for all users: https://index.torrust-demo.com/users/USERNAME

In this first iteration we can show only the username. I will create more issues to include new fields we want to use in the user's profile, like Bio and Avatar. When we open those issues, we should include a note to add them to the public profile.

Discussed in #90

^{Originally posted by BelieveInBunny June 8, 2022}

User profile section where everyone can see the post of specific user by clicking on his name from the post.