[SUP] Create function to get user data for My Space page

[wiktoriasalamon]

There is a need to refactor fetching user data for My Space page (frontend/src/app/(app)/(root)/my-space/page.tsx).

Create a new function in supabase.

Data should be fetched by user id (or for authenticated user if possible).

Get all user data from profiles table.
Get data from user_ladder for the current user (if there is more than one row for the user return only the row with is_main_ladder = TRUE).
Get data from band table for the ladder selected from user_ladder table.

For more details on which columns are needed check the file: frontend/src/app/(app)/(root)/my-space/page.tsx.