Reorganize the sales team's front page in the handbook

I'm re-organizing the sales team's front page in the handbook to make it a little more manageable and/or less overwhelming for readers.

It looks like well over 50% of the page is dedicated to the "How we use our systems" header, so that seems like low-hanging fruit for a standalone page, but I want to make sure that any links that may exist throughout the site pointing to that section of the page are updated also

My current working strategy is to move just the sales order processing section to its own page. It makes for a cleaner, more relevant link and also more evenly distributes content between two pages.

cc @sytses