rpk: evolve the usability of `rpk topic describe`

[daisukebe]

Who is this for and what problem do they have today?

In the field, we frequently want to get all topics' conf and partitions. In order to get it, we have to run something like this today, which doesn't look neat:

for T in $( rpk topic list -i | awk '!/^NAME/ {print $1}' ); do rpk topic describe $T -a ;done

What are the success criteria?

Enhance rpk topic describe

• by supporting multiple topics
• by supporting the regex flag like rpk topic delete has today.
  • rpk topic describe '.*' -r - we could maybe even support a bare * as a shortcut for .*

Why is solving this problem impactful?

Improve UX with rpk

JIRA Link: CORE-2711