Add new scripts to move review cursor by page (#14021)
Closes #13157 (given microsoft/terminal#13756). Supercedes #13671.
Summary of the issue:
There is no way to move the review cursor by page. This is especially useful in terminals as a "page" can be defined as a screenful of text, solving #13157 without violating any other assumptions in NVDA and still permitting easy jump to the absolute top/bottom of the terminal buffer using the currently existing scripts.
Description of how this pull request fixes the issue:
Added new scripts (bound to NVDA+pageUp/NVDA+pageDown on desktop and NVDA+Shift+pageUp/NVDA+Shift+pageDown on laptop) to move to previous/next page respectively.
