Http > Https redirect with a modification to the URL.

The system iRule "_sys_https_redirect" should do that for you.

It uses "HTTP::redirect https://[getfield [HTTP::host] ":" 1][HTTP::uri]".

From the documentation:

https://devcentral.f5.com/wiki/irules.getfield.ashx

To extract only the hostname from the host header (strips any trailing ":" port specification)

when HTTP_REQUEST {
  set hostname [getfield [HTTP::host] ":" 1]
}