This commit adds two small tweaks to the testing.adoc that demonstrates
how to import java based configuration into a unit test (instead of
importing XML based configurations).
This commit migrates the old Spring Batch documentation to a new
asciidoc toolchain. It will be the first piece in modernizing the
existing Spring Batch documentation. Future steps will include making
java based configuraion more prominant in the reference documentation.
Resolves BATCH-2620