New channels implementation for ORC (#17305)

* Update lib/std/channels.nim
* Rename tchannel_pthread.nim to tchannels_pthread.nim
* Rename tchannel_simple.nim to tchannels_simple.nim

Co-authored-by: Mamy Ratsimbazafy <mamy_github@numforge.co>

changelog.md

@@ -223,6 +223,9 @@
 
 - Added `jscore.debugger` to [call any available debugging functionality, such as breakpoints.](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/debugger).
 
+
+- Added `std/channels`.
+
 - Added `htmlgen.portal` for [making "SPA style" pages using HTML only](https://web.dev/hands-on-portals).
 
 - Added `ZZZ` and `ZZZZ` patterns to `times.nim` `DateTime` parsing, to match time
@@ -230,7 +233,6 @@
 
 
 
-
 ## Language changes
 
 - `nimscript` now handles `except Exception as e`.