Enable attaching the control bar to top and bottom

[tobfah]

This PR enables attaching the control bar to the top and bottom positions, in addition to the traditional left and right positions.

Tested on

• Fedora 42
  • Firefox 147
  • Chromium 144
• macOS 26.3
  • Safari 26.3
  • Chrome 144
• Win 11
  • Edge 145
• Android 13
  • Chrome 144
• iPad 26.3
  • Safari 26.3

[CendioHanli]

Tested the implementation on Epiphany v40.2 and Chromium v144 on Fedora 43 and found no issues. Regarding the decision to not use a relative offset for the noVNC_control_bar in the top and bottom positions look good. I found no instance where this caused any weird edge cases.
LGTM!

[samhed]

Funkar bra, har testat på Chrome (Linux) och Firefox (Android), mycket trevlig funktion!

Ifall slutresultatet är tänkt att ha uppdelade commits bör du nog nämna i alla commits vilken relation de har till huvudproblemet.

[tobfah]

I've restructured the PR a bit. A few changes since the initial one:

• The default left position returns as an implicit fallback for robustness (noVNC_left reverted)
• Rely less on local storage
• Separation of commits have been simplified and should make more sense on their own

Not sure why clipboard tests keep failing though.

[tobfah]

The last force push fixed some alignment issues with the handle arrow when control bar is in horizontal modes (top/bottom).

I've ran the tests on a RHEL 10.1 with nodejs 22.22.0 and npm 10.9.4, and they all pass on my side, so I'm not sure what to do with those that keep failing here.