chore: Add CI check for formatting

[lavaleri]

Issue #, if available:

Description of changes: Add check for formatting to CI, and format all code to adhere to google-java-format.

Notes:

• Add https://github.com/coveooss/fmt-maven-plugin to pom
• Add CI to specifically check the format
• Run autoformatter tool in order to pass this new check
• Point submodules to public repos

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

Check any applicable:

• Were any files moved? Moving files changes their URL, which breaks all hyperlinks to the files.

[seebees]

I vote that we only have the checks in the CI.

[lavaleri]

Used jardiff to determine that there is no bytecode change between a jar produced by this branch and master.

Used diff to ensure that javadocs produced by this branch and master have no difference, when stripped of newlines and <!--Generatedbyjavadoc(11.0.10)onWedMayXXXX:XX:XXPDT2021--> comments.

[lavaleri]

Reconfirmed that there is no difference in bytecode using jardiff between this branch and master.

[seebees]

Can we move this to https://github.com/aws/aws-encryption-sdk-java/blob/master/codebuild/compliance.yml?

[lavaleri]

@seebees You can to run the format check in the same build as the compliance check?

[seebees]

That is what I was thinking on the JS side, that is what I'm doing. I put the static code analysis all in one place...

[seebees]

Looks good. Can you add the jardiff and diff commands you used for posterity :)

[lavaleri]

To check byte code difference:

• checkout this branch, mvn clean, mvn install
• mv ./target/aws-encryption-sdk-java-2.3.0.jar ./after.jar
• checkout master branch, mvn clean mvn install
• mv ./target/aws-encryption-sdk-java-2.3.0.jar ./before.jar
• install jardiff: https://github.com/scala/jardiff
• jardiff before.jar after.jar
• confirm that any output is just pom or META-INF updates

To verify doc changes:

• checkout this branch, mvn clean, mvn javadoc:javadoc
• mv target/site afterdocs
• checkout master branch, mvn clean, mvn javadoc:javadoc
• mv target/site beforedocs
• strip newlines and <!--Generatedbyjavadoc(11.0.10)onWedMayXXXX:XX:XXPDT2021--> tags from both afterdocs and beforedocs using your favorite regex!
• diff -r beforedocs afterdocs
• confirm there is no output

[alex-chew]

LGTM