feat(MSRV): update to rust 1.66.1 and fix some warning

[joshuachp]

• Update the dependencies where is possible, some are still pinned by the astarte-message-hub
• Fix some warnings in a match state on the ota_handler
• Reorder the systemd module and remove the allow unused
• Check the result returned by systemd notify

[codecov[bot]]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.47% :warning:

Comparison is base (c04c4b3) 75.26% compared to head (f0b742d) 74.79%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #258 +/- ## ========================================== - Coverage 75.26% 74.79% -0.47% ========================================== Files 26 25 -1 Lines 1334 1329 -5 ========================================== - Hits 1004 994 -10 - Misses 330 335 +5 ``` | [Files Changed](https://app.codecov.io/gh/edgehog-device-manager/edgehog-device-runtime/pull/258?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=edgehog-device-manager) | Coverage Δ | | |---|---|---| | [src/lib.rs](https://app.codecov.io/gh/edgehog-device-manager/edgehog-device-runtime/pull/258?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=edgehog-device-manager#diff-c3JjL2xpYi5ycw==) | `75.94% <100.00%> (-4.68%)` | :arrow_down: | | [src/ota/ota\_handler.rs](https://app.codecov.io/gh/edgehog-device-manager/edgehog-device-runtime/pull/258?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=edgehog-device-manager#diff-c3JjL290YS9vdGFfaGFuZGxlci5ycw==) | `84.69% <100.00%> (ø)` | |

:umbrella: View full report in Codecov by Sentry.
:loudspeaker: Have feedback on the report? Share it here.