[CLI] Adjust slack thread parameter

[StefMa]

1. Right now users have to parse the URL by themself to get the timestamp and the channel id.
   We want to make this easier to use and introduce a --url on CLI level.
   This can then parse the URL, extract the channel and timestamp and put it into the summaraizer.

2. We want to rename channel to cid and ts to thread-ts. Just because these are the exact paraemters of the URl and it is probably better to understand what is expected by the CLI