bpo-30362 : Add list options to launcher. (#1578)

* bpo-30362 Add list options to launcher.

* bpo-30362 Add list options to help message.

* To avoid possible later conflict with python replaced flags with --launcher-list and --launcher-list-paths

* bpo-30362 Changed flag to -0 as suggested on review.

* bpo-30362: Modified to default to not path for -0, -0p to dispaly path and append * to default

* bpo-30362: Modified to display list on required version not found.

* bpo-30362 add --list and --list-paths added back in following review by paul.moore

* bpo-30362 Cleaner handing of -0 & -0p by not calling exit directly per review by @zooba

* bpo-30362: Tidy up and add news & what's new

Removed commented out line of code in PC/launcher.c.
Added the results of using blurb to add details of bpo-30362 & bpo-30291.
Updated Doc/whatsnew/3.7.rst to add a Windows only section covering both tickets.

* bpo-30362 Resolve conflict in Doc/whatsnew/3.7.rst

* bpo-30362:Address Whitespace Issue in Doc\whatsnew\3.7.rst

* Shorten NEWS message for bpo-30362

* Shorten NEWS item for bpo-30291