Implement GB speed signs

[Liaely]

Add GB speed signs, namely:

• Permissible Speed Directional Arrows,
• Permissible Speed Acceleration Indicator,
• Permissible Speed Indicators (for both kph and mph),
• Permissible Speed Warning Indicators (for both kph and mph),
• Enhanced Permitted Speed Indicators,
• Enhanced Permitted Speed Warning Indicators,

For speeds 5-125 mph/5-200 kph in increments of 5 for all possible speeds.
Both board & stencil designs.

Not including HST/LH/MU/DMU/EMU/SP/WES/LUL/CS/S7 specific Permanent Speed Restriction types, or Tyne & Wear Metro signs due to low relative usage and likely lack of proper tagging.
Not including Enhanced Permitted Speed differential signs due to low usage and likely lack of use.
Not including differential speed signs due to the level of work relative to likely tagging usage.

[Liaely]

I will be working on this.

[hiddewie]

Thanks, it would be great to implement these!