Naming of submodules

Issue information

From user: jurgenhaas

Contribution record

Fork management

Problem/Motivation

Let's review the naming and descriptions of modules and all submodules. There have been some touch point before in the following issues:

• #3238464: Move any plugin implementation into a separate sub-module, in order to let eca be the core API
• #3227666: Implement action "Trigger another event"