Not needed AWS dependencies included to project

[martinsefcik]

In spring-content-s3 module I guess It should be enough to not depend on:

               <dependency>
		    <groupId>com.amazonaws</groupId>
		    <artifactId>aws-java-sdk</artifactId>
		    <version>1.11.905</version>
		</dependency>

but instead only on:

               <dependency>
		    <groupId>com.amazonaws</groupId>
		    <artifactId>aws-java-sdk-s3</artifactId>
		    <version>1.11.905</version>
		</dependency>

Because otherwise a lot of aws-java-sdk jars are included into project and I think they are not needed.

Currently the following workaround can be used to exclude aws-java-sdk in project which uses spring-content-s3 and add only aws-java-sdk-s3 as dependency.
Example for gradle:

    implementation('com.github.paulcwarren:spring-content-s3-boot-starter:1.2.0') {
        exclude group: 'com.amazonaws', module: 'aws-java-sdk'
    }
    implementation 'com.amazonaws:aws-java-sdk-s3:1.11.905'