Make a top-level ICE pom.xml from org.eclipse.ice.build

[marshallmcdonnell]

From the off-topic discussions in a closed issue, had discussions to potentially move the pom.xml file in org.eclipse.ice.build pom file to the top-level of ICE:

Key conversation links:

• Suggestion part 1: Migrate or replace BATS capability into ICE #475 (comment)
• Suggestion part 2: Migrate or replace BATS capability into ICE #475 (comment)
• Response: Migrate or replace BATS capability into ICE #475 (comment)

Would like to move this to the top-level so ICE has one "main pom.xml" file.
Will help using JitPack in other projects that have ICE sub-projects as dependencies (example for multi-module repo)