Add search functionality

[uwegeercken]

Problem description

The capability to search for "things" helps to increase the developer/user efficiency to

• find steps by name
• find fields or variables by name
• find text in notes
• find text in formulas

Preferred solution

Search should be able to search the currently active flow but also other flows open in the GUI. Search might be valuable also across the workspace/project folder or another defined location.