Use revapi to generate list of API changes

[dlmarion]

I'm going to close this PR, but wanted to capture what I did to generate the list of API changes in apache/accumulo-website#461. With the changes in this branch I ran a Maven
build sending the output a file. Then I sorted that file and manually fixed it up, then copied it over to the
website branch I was working in.

mvn clean verify -DskipTests -DskipITs -DskipQA -Papi-diff 2>/tmp/api
cat /tmp/api | sort -u > /tmp/api-sorted
vi /tmp/api-sorted, remove line starting with npx, fix table header

I found that running the plugin produced inconsistent results, either producing 123, 147, or 1628 lines of output. It seems like there is an issue filtering the files with the regex. 1628 included a bunch of files outside the public api definition. The difference between 123 and 147 were some files in the minicluster module. I took the 147 line file and copied that over to the website branch.

[dlmarion]

Closing this as I'm not intending to merge this, but merely capture the information.