Timelib 2021.17 integration, with bug fixes

[derickr]

Fixes:

• Fixed PHP Since PHP 8.1.7 strtotime translates a date-time with DST/non-DST hour differently based on default timezone #9165: strtotime translates a date-time with DST/non-DST hour differently based on default timezone
• Use const correctly, and other compiler warning fixes
• Added test case for PHP's DateTime::diff doesnt evaluate daylight saving time correctly  #9382
• Add test cases for PHP DatePeriod with 1 hour DateInterval misses hour on long DST day #8860

Datafile:

• New 2022b data file
• Use new 'PACKRAT' format to prevent old timestamps from becoming incorrect

[Girgias]

Seems you need to add some const qualifiers to ext/date.