Badly named methods

[AntoineMazuyer]

Some functions are badly named e.g.

https://github.com/GEOSX/GEOSX/blob/b1224b9d6f190bb6f44025c687b3c46f18f36c28/src/coreComponents/mesh/EdgeManager.hpp#L142-L146

that are returning an index, not a list.

Maybe we have to do something more general with the methods naming (ensuring CamelCase, checking if the name of the method is right etc.)

[corbett5]

Yeah we have a lot of methods that are pascal case still like GetGroup. I would say that we should just delete these two methods and similar accessors. Users should pull out the edge to node map and then use it instead of calling methods.

[rrsettgast]

This is from before we had a standard of practice of just returning a reference to a view of the underlying object. These should be removed.

[TotoGaz]

The issue is a bit too broad to bit assessed. I'll close it for now.