Address checkstyle errors in Media Service code

[jcookems]

The new Media Service code has 261 checkstyle errors, most of which are trivial fixes. These should be addressed.

[jcookems]

Classifying the issues:

Issue	Count
Field should be property	150
Name must match pattern	31
'static' modifier out of order with the JLS suggestions.	24
Redundant 'public' modifier.	14
Class should be final	11
Magic Number	10
Redundant throws	10
Missing package-info.java file.	4
Utility classes should not have a public or default constructor.	3
'if' construct must use '{}'s.	2
Unused import	1

Commens:

1. The first issues is going to take some effort to fix, and we need to decide if that is something that we want or need to do.
2. The second issue is mostly complaints about the JAXB generated names, but our general approach has been to leave those files untouched. Ideally, we could add metadata to exclude those files from the style-check.
3. The third issues is also mostly in the JABX files.

[jcookems]

Have a PR that fixes some of the issues (https://github.com/jcookems/azure-sdk-for-java/pull/5), leaving:

Issue	Count
Field should be property	150
Name must match pattern	21
'static' modifier out of order with the JLS suggestions.	22
Class should be final	12
Missing package-info.java file.	4

[andrerod]

We should be golden in checkstyle errors. Checkstyle is now a part of the build process.