[FEATURE] Expand functionality of Set-PnPPage to set default selection for Page Template

[paxvas2023]

When creating a new page from the startpage i enter the page templates dialog where i can choose the template I would like to have. But I am also able to set a default selection for templates. This option is until now not available in the command Set-PnPPage. There I can set the parameter -PromoteAs Template, but i have no option to set a default template.

When I have 3000 Site which should use a custom page template and I have to do that manually it would take a lot of time and with an simple powershell command which would be useful for many clients this could be established very fast.

As solution I propose to expand the values of parameter -PromoteAs with a new value DefaultTemplate to establish the functionality.