Child of SlackRubyBot::Bot migration to Slack Socket Mod

[mr-exz]

Hello, I was happy user of this gem for 5 years, but Slack introduced braking changes and I had to migrate fast bot to continue have it working
Can you take a look into this PR and drop some suggestions how better reorganize changes https://github.com/mr-exz/whoisondutytoday/pull/201/files

I want based on my changes create PR into slack-ruby-client to support Socket Mod properly
Then create PR into slack-ruby-bot to have it supported there
Then migrate my bot to new version of that gems with needed implementation
Can you help with it ? From you I need some hints what needs to be changed or where to look, for me was hard dig alone