Add new database tables and the associated operations for profile selectors

[jhrozek]

We need to add the table and the basic CRUD operation for the table

[jhrozek]

Table would look somewhat like this:

CREATE TABLE IF NOT EXISTS profile_selectors (
  id UUID NOT NULL DEFAULT gen_random_uuid() PRIMARY KEY,
  profile_id UUID NOT NULL REFERENCES profiles(id) ON DELETE CASCADE,
  entity entities, -- this is nullable since it can be applicable to all
  selector TEXT NOT NULL, -- CEL expression
  comment TEXT NOT NULL, -- optional comment (can be empty string)
);

-- Ensure we have performant search based on profile_id
CREATE INDEX idx_profile_selectors_on_profile ON profile_selectors(profile_id);