Improved CLI docs and add prompt to confirm index create overwrite.

[fmassot]

Description

Improve CLI docs and add prompt to confirm overwrite. By default, the answer is no. A flag "-y --assume-yes" is here

Note

I like having a better XP on the CLI. Unfortunately, the current code I introduce is lame as it's very specific to one command.

I think other risky operations should behave the same way.

prompt

yes

no

How was this PR tested?

With the current tests.