PR Summary

Make explorer context menu registry entries platform specific to allow them to work also when both x86 and x64 are installed. The main menu has a " (x86)" appended to the main menu as well.
This issue was found a few days after the context menu was merged into master in an unrelated issue by @iSazonov
Some renaming was applied to existing variables to distinguish better between main menu and sub menu

PR Checklist

Note: Please mark anything not applicable to this PR NA.

• PR has a meaningful title
  • Use the present tense and imperative mood when describing your changes
• Summarized changes
• [NA] User facing Documentation needed
  • [NA] Issue filed - Issue link: Found a few days after the initial feature was merged
• Change is not breaking
• [NA] Make sure you've added a new test if existing tests do not effectively test the code changed Manual test only.
  • [NA] Add [feature] if the change is significant or affects feature tests
• This PR is ready to merge and is not Work in Progress.
  • If the PR is work in progress, please add the prefix WIP: to the beginning of the title and remove the prefix when the PR is ready.