Update O&M Manual w/ correct ENV variables on frontend/backend Cloud.gov apps + HHS CircleCI project settings

[kniz-raft]

Environment variables in our frontend and backend cloud.gov apps have been updated per 1179 comment and also includes additional variables for the SFTP file transfer for release 2](#1133 (comment)). Similarly, env variables in HHS CircleCI project settings have been updated accordingly. As such, the Operations and Maintenance manual, which includes descriptions of these variables, needs to be updated.

AC:

• Update Ops manual

[ADPennington]

@jtwillis92 @abottoms-coder can we discuss this at this week's tech sync?

[jtwillis92]

For additional reference: #1179 (comment)

[ADPennington]

closing this as a dupe to #1422 which will be more comprehensive re: release 1 ato doc updates cc: @valcollignon @lfrohlich