Upgrade Gradle to 7.3.3 & Android Gradle Plugin to 7.1.1

[oguzkocer]

This PR updates Gradle and Android Gradle Plugin to their latest versions. It also addresses issues that resulted from the upgrade with the goal of getting a successful ./gradlew build command. It removes publishing related code - as it's no longer usable - in favour of adding publishing to our S3 Maven in a subsequent PR.

• In 747e109, Gradle wrapper is updated with the ./gradlew wrapper --gradle-version 7.3.3 --distribution-type all command.
• 577e58b updates Android Gradle Plugin to its latest version 7.1.1.
• acfc832 adds android.useAndroidX=true to gradle.properties. In PermissMe library gradle.properties was ignored, so gradle.properties-example was introduced for this. However, since gradle.properties is already checked into the project, adding the android.useAndroidX property is simpler. I think this is something we should address in the future to bring consistency across projects, however I don't think this PR is the right time & place to do it.
• a87cea3 removes Bintray & Maven plugins. These are no longer supported (or needed) and will break the build.
• 3826905 removes the buildToolsVersion property which is no longer necessary and gets ignored by AGP.

To test:
I unfortunately don't have any testing instructions for the project, but these are all build related changes and at least those can be verified by ./gradlew build command which builds, tests and lints the projects. It'd be helpful to smoke test the example app if the reviewer is familiar with it.

[oguzkocer]

@obsantos This PR supersedes both #16 & #21, so I think we should close them. What do you think?

[obsantos]

This PR supersedes both #16 & #21, so I think we should close them. What do you think?

Yea lets close them!

Looks good 💯