feat: disable env variables and add list endpoint

[maximka76667]

• I added an endpoint to return a list of available artifacts. I tried to follow the same practices as the original code.
• Also I disabled env variables for now and replaced them with some string literals
• Also I modified upload endpoint to include id of uploaded file in the return type

[Humanoidear]

Hardcoding password and secret is really bad. Regardless I suggest an easier method for authentication, will discuss at the meeting.