Support S3 locations

[JonLally]

Support s3 locations by use of aws-java-sdk-s3.

Issue references: #1961 #1779

• I'm not 100% sure of some of the changes I made, specifically the entry in the flyway-core pom for the maven bundle plugin.
• I also had to explicitly specify 4.5.2 version of the httpclient from apache http components, it is a transitive dependency of aws-java-sdk-s3 and updating the order of the dependencies didn't matter as it took the version from google android always.
• I'm unsure of the testing process, I've had to manually test this but if there is an automated suite I can contribute to I'd like to provide tests around this functionality.

[CLAassistant]

All committers have signed the CLA.

[mack1040]

Nice work - we have needed this feature for a while

[carlitos081]

Finally!!!

[KiruthikaSS]

Eager to know, when this feature will be released. Any Milestone planned? Plz let me know.

[juliahayward]

Many thanks for the contribution (and welcome to the hall of fame!) We're looking at including this by 6.3 - including tests at our end and documentation changes.

[juliahayward]

Do have a look at #2664 - this came up with both AWS SDK 1.11 and 2.0. We would strongly prefer to use the v2 SDK (which requires some code changes, although they are pretty mechanical and I have done them) however that requires Java 8 - any thoughts?
.

[JonLally]

Wasn't aware of the AWS SDK v2, would definitely agree with using it instead of 1.1.

[Lyeeedar]

Moving this to flyway 7.x as the v2 SDK requires upgrading flyway from java 7. See #2458 (comment)