How do I deploy custom ASPX pages to SharePoint 2016? I mainly have experience in 2007/2010 setups, so I know "things have changed" in SharePoint 2016 on premise. I know in the old days you could use WSPBuilder to package your wsp solutions and run stsadm to deploy your solutions, but it seems there are other ways of doing things these days.
Long story short, I am needing a custom ASPX page to live in the _/layouts folder that can be accessed like http://sharepoint_domain/_layouts/15/somefolder/mypage.aspx
We are going to me making our own version of the WOPIFrame.aspx page that is used between SharePoint 2016 and Office Online Server.
Thanks in advance!