While there, switch to the defaults when reloading the webgui.

I know, I know, backing up rrd and restoring it after reboot seems
like overkill, but the good thing is that if you ever decide to
install from a clean image the config import is able to pick up
your backups as well and you will not lose any history.

* Renamed pfsense-utils.inc to legacy.inc, which can cause issues
  on git auto-mount developer machines.  Be wary.

* Removed '/usr/local/www/' prefix from require statements that
  should never use absolute paths (unless you are never going to
  move files, but we already did...).

* Remove an unhealthy function that wrote arbitrary PHP files and then
  style checked them, twice.

* The usual license cleanups so that the headers are easy to read
  and actually make you want to see the rest of the file because of it.

* Code style, indent and obvious bug fix (missed unlock in return path).

This allows us to grep for the file name as "name.something.xml"
and still be able to find the variable or path or binary or so,
while the actual file name is only set once avoiding typos in the
process as well...

fix for https://github.com/opnsense/core/commit/06ff13943b3cddc378005bcd8995c105bb8057a0#commitcomment-10034901

add https://github.com/nakupanda/bootstrap3-dialog to standard codebase to ease jQuery/bootstrap dialogs