[SQL] Sql midb Add: update/show long term retention policy, show/delete long term retention backups, restore long term retention backup

[xaliciayang]

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[yonzhan]

add to S167

[jaredmoo]

I would love if the length of short-term-retention-policy can be aggressively reduced in length. Try typing this 10 times in a row and I'm sure you would not want to be a customer using this command repeatedly :) Ergonomics is more important than clarify here - abbreviations can be easily explained with help text, as has been done for sql mi, sql midb, etc. My first idea is just short-term, but there are more possibilities.

[Juliehzl]

Please add checks for all your test commands to make sure commands output is as expected.