Feat: --attended=false to skip user prompts

[OjusWiZard]

Allow skipping user prompts in the QS

[jmoreira-valory]

If it's not a lot of work, can we consider having the negate environment variable instead? UNATTENDED ?

[OjusWiZard]

@jmoreira-valory I started with that, but then went with ATTENDED to avoid double negation when checking if it's "not unattended". I believe it's more understandable to say "attended". More explained here

[jmoreira-valory]

@jmoreira-valory I started with that, but then went with ATTENDED to avoid double negation when checking if it's "not unattended". I believe it's more understandable to say "attended". More explained here

@OjusWiZard Yes you are absolutely right about confusing conditionals. However, the term "unattended installation" is a quite common accepted term in software deployment processes, that's why I suggested it. Also there is a bit unmatching the flag --unattended and the environment variable ATTENDED. Not mandatory to change it, though, I let you decide what's the best option in this case. (I accept the PR anyways to avoid delay merging it.)

[0xArdi]

@OjusWiZard please rebase to develop. Changes look good.