Write a quick doc with instructions for some dev release tasks

Description

Write a quick doc with instructions for:

1. Cutting release branches.
2. Putting the CI servers and translation server onto release branch.
3. Investigating build issues such as when an RC fails to build.
4. Updating servers to latest build / dot release version where needed.

QA Test Steps

None

Status

Mana

None

Assignee

Carlos Panato

Reporter

Amy Blais

Epic Link

None

Fix versions

Mattermost Team

Cloud

Sprint

None

Labels

None

GitHub Issue

None