Removing scala test infrastructure

[lbergelson]

• We tried adding support for scala based tests but it never really caught on. It did complicate the testing infrastructure and reporting considerably and caused complication in the build.
• Removing scala and scala test and the associated gradle plugins
• Updating gradle 5.2.1 -> 7.5.1
• Converting from the java plugin to the java library plugin

This leaves in place the now defunct scala tests:

• FastqReaderWriterTest
• AbstractProgressLoggerTest
• StringUtilTest
• BamFileIoUtilsTest

These will need to be back ported to java. This allows us to move to a new version of gradle and eventually to new jvm versions in a much simplified way. It also looks like it may speed up the tests.

[cmnbroad]

@lbergelson Were we previously exporting all of our dependencies, and if so, are we going to break clients now by having a narrower surface area ?

[lbergelson]

@cmnbroad I'm hoping we don't.... I don't believe we export any of the newly implementationed ones in our public API but I don't know how to check that automatically. It might cause issues for people who are depending on ours for their own cod without realizing it, but that should be an easy fix for them. If know how to check the API in a sane way that would be very useful, it's definitely something a tool could exist for.

[cmnbroad]

@yash-puligundla This PR might fix the "no test events" issues you were previously seeing (I seem to remember thinking that scala-test was implicated for that). You might rebase on this once it goes in.