Updates to Accommodate React Router 6

[mwislek]

Updates the client template subsection generator to accommodate React Router 6. See https://github.com/LaunchPadLab/client-template/pull/485 for the client changes that prompted this update.

To test this:

1. Pull down the latest from this repository and switch to the feat/react-router-6 branch.
2. Execute yarn link in the root of this project
3. Navigate to a local copy of the client-template repository and pull the latest from the main branch.
4. Execute yarn link "@launchpadlab/lp-subsection-generator" to use the local subsection generator
5. Generate a subsection. For example, to generate the accounts subsection execute yarn generate-subsection accounts in the client-template project root folder.
6. Integrate the accounts subsection into the main <AppRouter> component.
7. Start the client template and verify that:
   a. You can navigate to the new accounts subsection, i.e., http://localhost:8080/accounts
   b. That the accounts index view is displayed
   c. You can navigate to the a specific account, i.e., http://localhost:8080/accounts/3
   d. That the accounts show view is displayed.
8. Verify that navigating back to the /home route is still functional.
9. Verify that navigating to the /styleguide is still functional.

[mwislek]

The real change was here. The rest of these changes were formatting.