Create registry key to force secure mode (#15049)
Fixes #10018
Summary of the issue:
System administrators may wish to configure NVDA to restrict unauthorized system access.
Secure mode can be forced through the --secure CLI parameter, however, forcing this parameter is not easily done for system administrators.
In a corporate environment where application usage is restricted, NVDA should be forced into secure mode via a registry key parameter, rather than a CLI parameter
Description of user facing changes
Added a registry key parameter to force secure mode of NVDA.
Improved documentation for system administrators on secure mode.
Description of development approach
Added a registry key parameter to force secure mode of NVDA.
make isRunningOnSecureDesktop and isLockScreenModeActive part of public API
