[server + web] Edit account settings functionality

[Kuchteq]

This issue has a prerequisite of #35

Server

• Add a GET path handler at /profile that would retrieve the current data on the user. That would include the profile picture, display name and username. Modify the openapi.yml spec file and implement the newly generated handler interfaces.
• Add a PUT path handler at /profile that the user would submit the changes they would like to make to their account. Modify the openapi.yml spec file and implement the newly generated handler interfaces.

Web

The following is supposed to be implemented as specified per the figma file. i.e.

• Add a new account settings page and fetch the necessary info from GET /profile. Skip this if the path is not ready and use hardcoded values.
• Add a profile picture section with the header, image and two buttons.
• Add a basic information section with the two fields, one of which is unmodifiable.
• Add the save changes button that only appears once the user has made any changes to the profile.