Add productivity software to the Spending Company Money page

This MR is part of my onboarding issue (https://gitlab.com/gitlab-com/people-ops/employment/issues/559). The intention is to start a discussion about being reimbursed for productivity software purchases. The handbook recommends a number of paid apps - it would be great to support these recommendations with a spending policy.

This MR throws out $100 USD as a starting point for discussion. This amount (if any) is entirely up for debate!