feat(timezone): improve ux and time zone handling #562

Job	Run time
Clippy (stable)	2m 40s
Clippy (Future) (beta)	33s
Clippy (Future) (nightly)	2m 39s
Build docs (stable, macos-latest)	30s
Build docs (stable, ubuntu-latest)	15s
Rustfmt	12s
Build docs (stable, windows-latest)	48s
Check MSRV (pace-rs, 1.74.1)	2m 14s
ubuntu / stable / features	2m 32s
Check MSRV (pace_core, 1.74.1)	1m 53s
Test (stable, macos-latest)	6m 51s
Check MSRV (pace_cli, 1.74.1)	2m 10s
Test (stable, ubuntu-latest)	3m 33s
Test (stable, windows-latest)	6m 26s
Test (beta, macos-latest)	5m 20s
Test (beta, ubuntu-latest)	3m 17s
Test (beta, windows-latest)	3m 18s
Result (CI)	0s
	45m 11s

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