[services] Change dev-mode to sandbox

Summary:
Following the @ashoat comments and @varun comments in D4253, it's better to remove the "jargon" dev-mode from the services commands and change it to 'sandbox'.

This diff is a refactoring dev-mode to sandbox.

Linear task: ENG-1299

Test Plan: Running yarn run-[service-name]-service-in-sandbox do the same as previous yarn run-[service-name]-service-dev-mode

Reviewers: karol-bisztyga, palys-swm, varun, ashoat

Reviewed By: karol-bisztyga, palys-swm, varun

Subscribers: palys-swm, Adrian, atul, karol-bisztyga, yayabosh, ashoat, varun

Differential Revision: https://phab.comm.dev/D4368