Multiple minor fixes

[jmcarcell]

BEGINRELEASENOTES

• Don't use the deprecated service retrieval
• Add final when possible and use the default destructors instead of implementing them
• Use ! instead of not in if(...)
• Use ! instead of comparing to nullptr
• Simplify setting the environment for tests, avoiding having to duplicate the names
• Clean up some includes in header and source files

ENDRELEASENOTES

[m-fila]

There are a few more destructors that could be cleaned-up (or removed according to rule of 0):

• ~LcioEvent
• ~LCEventWrapper
• ~LcioEventOutput
• ~MarlinProcessorWrapper
• ~TrackingCellIDEncodingSvc

[andresailer]

For my own elucidation: why not not?

[jmcarcell]

By convention, we use ! almost everywhere.

[tmadlener]

We are not really consistent with override and final here. Sometimes we use both, sometimes only one. I have a few examples below.