[Security analysis] Allow to monitor dangling lines

[sylvlecl]

• Do you want to request a feature or report a bug?

Feature

• What is the current behavior?

#1737 introduces the possibility to monitor specified branches, buses, and three winding transformers. By this, we mean getting results for those equipments out of a security analysis. The monitoring of dangling lines has not been implemented.

• What is the expected behavior?

The monitoring of dangling lines should be supported.

• What is the motivation / use case for changing the behavior?

Being able to request results for dangling lines (think tie lines etc).