Better times module (#6552)

* First work on better timezones

* Update tests to new api.
Removed tests for checking that `isDst` was included when formatting, since `isDst` no longer affects utc offset (the entire utc offset is stored directly in `utcOffset` instead).

* Deprecate getLocaltime & getGmTime
* Add `now()` as a shorthand for GetTIme().inZone(Local)
* Add FedericoCeratto's timezone tests (#6548)
* Run more tests in all timezones

* Make month enum start at 1 instead of 0
* Deprecate getDayOfWeekJulian
* Fix issues with gc safety
* Rename TimeInfo => DateTime
* Fixes #6465
* Improve isLeapYear
* FIx handling negative adjTime

* Cleanup:
- deprecated toSeconds and fromSeconds, added fromUnix and toUnix instead (that returns int64 instead of float)
- added missing doc comments
- removed some unnecessary JS specific implementations

* Fix misstake in JS `-` for Time

* Update usage of TimeEffect
* Removed unecessary use of `difftime`
* JS fix for local tz
* Fix subtraction of months
* Fix `days` field in `toTimeInterval`
* Style and docs
* Fix getDayOfYear for real this time...
* Fix handling of adding/subtracting time across dst transitions
* Fix some bad usage of the times module in the stdlib
* Revert to use proper time resoultion for seeding in random.nim
* Move deprecated procs to bottom of file
* Always use `epochTime` in `randomize`
* Remove TimeInterval normalization
* Fixes #6905

* Fix getDayOfWeek for year < 1
* Export toEpochDay/fromEpochDay and change year/month/monthday order
* Add asserts for checking that the monthday is valid
* Fix some remaining ambiguous references to `Time`
* Fix ambiguous reference to Time

lib/posix/posix_linux_amd64.nim

@@ -12,8 +12,6 @@
 
 # To be included from posix.nim!
 
-from times import Time
-
 const
   hasSpawnH = not defined(haiku) # should exist for every Posix system nowadays
   hasAioH = defined(linux)
@@ -40,13 +38,15 @@ type
 const SIG_HOLD* = cast[SigHandler](2)
 
 type
+  Time* {.importc: "time_t", header: "<time.h>".} = distinct clong
+
   Timespec* {.importc: "struct timespec",
                header: "<time.h>", final, pure.} = object ## struct timespec
     tv_sec*: Time  ## Seconds.
     tv_nsec*: clong  ## Nanoseconds.
 
   Dirent* {.importc: "struct dirent",
-             header: "<dirent.h>", final, pure.} = object ## dirent_t struct
+            header: "<dirent.h>", final, pure.} = object ## dirent_t struct
     d_ino*: Ino
     d_off*: Off
     d_reclen*: cushort