Do not run install sripts for pre-built binaries

This would hang the installation

ticket: #2200
Giving it another thought, that should be handled in the ports repo

Revert "Do not run install sripts for pre-built binaries"

This reverts commit 47dcabf01000999da186ec6456bd583796cb1187.
Enable xhci module by default for 9.1

A lot of time has been passed and the code has been improved.
Hopefully that wont be an issue anymore.

ticket: #2151
Do not create swap for log or cache devices

ticket: #2136
Give the user an error in case parse failed

ticket: #2190
Resize and position the dialog after clicking Adbanced/Basic mode
Add extra fields to bind NFS services ports

Optional fields to specify bind ports for mountd(8), rpc.statd(8)
and rpc.lockd(8).

ticket: #2203
shells/bash has changed to OptionsNG
Allow mountd(8), rpc.statd(8) and rpc.lockd(8) bind ports

ticket: #2203
Use simple text input widget for new NFS port fields
i386 kernel does not have KDTRACE_FRAME
Do not build plugin jail with WITHOUT_USB

It is required to build some packages within the jail due to
libusb*.
Use file:// for git cache repos
Subversion is in our past
Set quota and reservation as advanced fields for dataset
Allow creating a dataset with a custom recordsize

ticket: #1598
Return just the errors for dataset create

It was returning the whole page, and not just the JSON object
describing the errors. It would lead to advanced fields with
errors being hidden.
Dojo is now at 1.9.0
SECURITY: Check SHA256 hash of the upgrade image before proceeding
any further.  Proceeding with the pre-install checks, which are
scripts uploaded by the user without doing any sanity checks is a
very bad idea.

Note that because we do not yet do any signing over the upgrade
images, this is not a big problem yet, as the operation is limited
to the system administrators only, but better safe than sorry.

While I'm there, also assert that the form did gave us a sha256
checksum, which is guaranteed by the form itself.
Eliminate stale comments.