Draft: Disable fstrim timer and service on install

In 0dd1064b fstrim timer and service were disabled by default, which works fine for v2023dev3. However, in v2022 this approach is not enough since on image generation the older util-linux version is installed initially and then upgraded from -security.

Fix the issue by force disabling the timer and service on install.

infrastructure/apertis-issues#70 (closed)

Signed-off-by: Walter Lozano walter.lozano@collabora.com