Lots of spots where we did weird things around streams like redundant stream creation, redundant collecting
before adding all the collected elements to another collection or so, redundant streams for joining strings
and using less efficient `Collectors.toList` and in a few cases also incorrectly relying on the result being mutable.
Our spotless configuration wasn't being applied to `build-tools`
and `build-tools-internal`. Move the Spotless configuration to a
Java plugin in `build-conventions`, and apply it everywhere.
This resulted in a lot more Java files being subject to formatting,
so I added more exclusions to the list.
Also remove the `paddedCell` stuff, we've never needed it.
By using a BuildService we can decouple the configuration of projects but keep making
expensive operations (e.g. parsing properties file or reading minimumJavaCompiler from file) only once
per build.
This bring us closer to decouple projects and get ultimatively configuration cache compliant. In
general we will bring in more BuildServices for the main build to follow along that Pattern and
ultimatevely remove usages of allprojects and subprojects in our build.
This moves the public build api and plugins into a separete included build called 'build-tools'
and we removed the duplication of included buildSrc twice (2nd import as build-tools).
The elasticsearch internal build logic is kept in build-tools-internal as included build which allows us better handling of this project that its just being an buildSrc project (e.g. we can reference tasks directly from the root build etc.)
Convention logic applied to both projects will live in a new build-conventions project.
