Implement zoneinfo parsing/compilation and add TZif structs #885

Job	Run time
Lint	27s
MSRV	27s
Test (stable, ubuntu-latest)	26s
Test (stable, macos-latest)	27s
Test FFI (stable, ubuntu-latest)	19s
Test (stable, windows-latest)	1m 3s
Documentation	25s
Test feature matrix	2m 37s
	6m 11s

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