main/meson: change auto-features from 'auto'

In the abuild-meson auto-features should not be set to auto since this can cause different package outputs depending on the environment (reproducible builds).

!6271 (merged) suggests disabling auto-features by default but enabling it by default also has some advantages. For example if a previously enabled by default feature is changed to auto it would not get silently removed.

CC @fcolista