Add clippy to CI

[TorstenStueber]

It would probably be beneficial to add clippy checks, as they are disabled right now. We can use the same rules we already use in Spacewalk.

[TorstenStueber]

Hey team! Please add your planning poker estimate with Zenhub @b-yap @bogdanS98 @ebma @gianfra-t @TorstenStueber

[TorstenStueber]

Also note that there is this ticket, which we could add as well: pendulum-chain/spacewalk#153

[prayagd]

@TorstenStueber closing this one as we have already have a duplicate one which is prioritized

[TorstenStueber]

@prayagd Please always link to the duplicate. Which one is it?

[prayagd]

@TorstenStueber you already mentioned in the above comments pendulum-chain/spacewalk#153 or are they different tickets?

[TorstenStueber]

I will open this ticket here. The other ticket is in a different repository and therefore we need separate tickets.