Add a paging feature to Text and LCD panels for non-script use

LCD panels and Text Panels (and all Display Surfaces) can show scripts, static text and images, or content generated by programmable blocks. In non-experimental mode, this is limited to scripts and static text with (rotating) images. Timer blocks and other blocks that trigger Actions can change this to "Offline" and back, but this is as much as can be done with respect to dynamic content.

I'd like to suggest a page feature, where a Display Surface can have two pages while in in text and images mode. Each page would have its own text content, colour, font size and image selection. There would be an additional action to "switch page" in cockpit toolbars, timer blocks, air vent actions, sensor actions, etc. which would switch the screen's display between the two pages. This would allow players to build systems with opposing outputs, such as "safe to enter" and "keep out", or "weapons active" and "weapons safe", rather than only being able to choose between the content and the word "Offline". This would greatly add to the usefulness of text screens in official multiplayer servers, or other environments where programmable blocks are not available.

I do understand that selecting the display surface to switch, when given a block with multiple displays, is slightly more complex; perhaps an action for each display would need to be added.