make integrate_profile() compatible with clean_mixture()

[adokter]

We need to add height-integrated values for the following quantities

• f

when present, mixture_u, mixture_v, mixture_airspeed, mixture_heading are present (when keep_mixture = TRUE), should generate height-integrated values

• mixture_vir
• mixture_airspeed
• mixture_airspeed_u
• mixture_airspeed_v
• mixture_heading
• mixture_u
• mixture_v