0.57.0 banner (#2368)
0.57.0 banner (#2368)

* 0.57.0 banner

* replace "replace this with the release date" with the release date

* Reorder changelog entries for 0.57.0

palantir/atlasdb,palantir/atlasdb,EvilMcJerkface/atlasdb,EvilMcJerkface/atlasdb,palantir/atlasdb,EvilMcJerkface/atlasdb