POC: Implement the new alias system, general parameter classes and some refactors

[seisman]

See #3239 for the detailed context.

This PR implements the new alias system proposed in #3239. It also add some new features and refactor some wrappers to show how the new alias system will affect the current codes.

Here is a summary of changes in this PR:

• pygmt/alias.py: Implement the new alias system
• pygmt/params/base.py: Implement the BaseParam class as a base class for other parameter classes
• pygmt/params/box.py: Implement the Box class, showing how to define new classes in a simple way
• pygmt/params/frame.py: Impement the Frame class, showing that the current design works work for the most complicated GMT option
• pygmt/src/basemap.py: Refactor so that you can try the new Frame parameter in Figure.basemap
• pygmt/src/dimfilter.py: How the new alias system can affect grid-related modules
• pygmt/src/image.py: How the new alias system can replace the old alias system
• pygmt/src/logo.py: Refactor so that you can try the Box class
• pygmt/src/scalebar.py: Initial implementation of the high-level wrapper for adding a scale bar.
• pygmt/src/timestamp.py: Figure.timestamp is one of the wrappers that don't use the alias system. Using the new alias system can simplify the code.
• pygmt/src/coast.py/pygmt/src/binstats.py: How to support long-form arguments

This is just the initial implementation. So, some doctests and tests are still missing. We will break this PR into multiple smaller PRs and make the implementation more robust after people generally agree with the design of the new alias system.