New rule: Prevent lazy continuation lines

[skwde]

This is somewhat related to MD032 and emerged from #972

Lazy line conditions make the markdown file less readable. That is because

1. abc
2. def
ghi

behave the same like standard lists

1. abc
2. def
   ghi

Even more confusing/weird is the behavior when using multiple levels like

- abc
  + def
ghi

where ghi goes to the 2nd indent level.

In addition, as mentioned in https://github.com/DavidAnson/markdownlint/blob/main/doc/md032.md some parsers do not parse lists if they are not surrounded by blank lines. MD032 is however only concerned with the starting line because it cannot know when it should be a lazy line continuation or when the list is done.

[BlaineEXE]

Ditto. This would be a great add :)