imp: added more common derives App, Arg, and ArgMatches

[budde25]

Closes #952

This is the current status (after the changes) of the the public types.

• App

  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default

• Arg

  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default

• ArgMatches

  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default

• Values

  • Copy
  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default

• ValuesOs

  • Copy
  • Clone
  • Eq
  • PartialEq
  • Ord
  • PartialOrd
  • Hash
  • Debug,
  • Display
  • Default

The only types that I was able to add were Eq, and PartialEq.
I also noticed that for Values and ValuesOs, it explicitly said that it didn't implement debug so I'm unsure if that is a design choice.

Regarding certain traits:

• Default is meaningless for Arg, App, ArgGroup.
• Implementing PartialOrd + Ord is probably next to impossible because they aren't implemented for IndexMap. Same with Hash

Originally posted by @CreepySkeleton in #952 (comment)

The three mentioned here already had explicit default implementations.

It also may be possible to add things like Eq, and PartialEq to Values and ValuesOs but it isn't possible as far as I can tell with default derive implementation. It seems to mostly be a limitation of std::slice::Iter