Mention automations as factor in Ref Arch selection

What does this MR do?

Adds a paragraph about considering runners, integrations & scripts in addition to human users for deciding which reference architecture to chose.

Support is regularly seeing performance problems due to automations being activated on instances, that may be too small to handle the amplified load.

Related issues

See "mentioned in" activity items below (some or all will be confidential). Inclusion of a particular case there does not mean that the customer's automation definitely was the root cause of a performance problem, but that its impact was at least remarked upon or investigated during an investigation.

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