Include a `javaxswing` directory

[Diptonil]

The following additions are to be made:

• Take a look at the javalang directory (it is incomplete as of now).
• A section that explains the javax.swing package in a similar way, with proper documentation, is required. That will be done under the javaxswing directory of the source.
• README is compulsory along with explanatory programs.
• Tests are not needed.
• Contributors with experience in tackling the Swing framework, knowledge of its features and nuances with the capability to explain exactly what the classes and methods do are requested to take on this issue.
• The packages java.awt or java.applet do not need to be dealt with here. It would be done separately.
• Expect multiple reviews and correction comments if tackling this issue.

[akashkeshriofficial]

Can you please assign me this issue?