Update Apache HTTP transport

[dmdashenkov]

The currently used v1 Apache HTTP transport lib is deprecated, as evidenced by warnings upon each build. We should update to the v2, as stated in the ApacheHttpTransport class-level Javadoc.

However, updating to v2 causes a series of dependency clashes that are hard to resolve. In particular, the v2 code includes some kind of a call to API which is not found at runtime. To reproduce this, update the artifact and run integration tests.

We will probably be able to update this artifact in the future more easily. It's best to try and do so before the Spine v2 release.

[armiol]

This is already done for Spine 1.9.0, but still needs to be addressed in Spine v2.