Hourly snapshots are created on the hour at x o-clock rather than after an hour of system uptime

[NintendoManiac64]

Describe the bug
Hourly snapshots are created at 1 o-clock, 2 o-clock, etc, rather than after 1 hour of system uptime, 2 hours of system uptime, etc.

To Reproduce
Steps to reproduce the behavior:

1. Have Timeshift set to make hourly snapshots
2. Turn off your PC
3. Two minutes before the hour, turn on your PC (e.g. turn it on at 11:58; you can also just set your BIOS or UEFI to such a time and just make sure to be disconnected from the internet)
4. Observe that, when the clock hits 12:00, a Timeshift snapshot will be taken

Expected behavior
Hourly snapshots should be taken after an hour of system uptime; in the example given, that would mean at maybe 12:58 or 12:59. This would put it in-line with how boot snapshots are taken when system uptime reaches 10 minutes, and makes more sense since you should want the boot snapshots to always be taken before the hourly snapshots.

(also the current behavior can have some funky things happen if the "on the hour" snapshot occurs while Mint is still fully booting up)

Screenshots

System:

• Mint 21.1 (upgraded from Mint 21.0)
• Cinnamon
• Timeshift v22.11.1 and v22.11.2

[DJCrashdummy]

IMHO it is not really necessary to have (all) the timed snapshots taking place in its certain distance from a (re)boot... think of daily, weekly or monthly snapshots: they would hardly ever happen!

but i'll give you that: it seems that the possibility that a snapshot takes place immediately at booting is not ideal. hence IMHO for all timed snapshots it should be checked if uptime > delay for @reboot-snapshots and if not, wait for the difference and only then actually take place.

if that's not really necessary resp. not considered a bug, i would be interested in why the @reboot-snapshot has a (hardcoded) delay ingrained.