Upgrade Liquibase to latest version; remove final Java source file and need for `clojure -X:deps prep` (#20611)

* Upgrade Liquibase to latest version

* Try adjusting log

* Fix checksums for the TWO migrations with ID = 32

* FINALLY get Liquibase to use Log4j2

* Set Liquibase ConsoleUIService OutputStream to null OutputStream

* Manually define a package for our H2 proxy class so Java 8 works

* Fix package-name determination code

* Update migrations file spec

* `databasechangelog` shouldn't be upper-case

* Lower-case quartz table names

* More MySQL fixes 

* Properties for all the Quartz tables 

* Formatting tweaks [ci skip]

* Revert a few more busted changes

* Fix more busted changes

* Bump Liquibase version to 4.8.0 to fix MySQL defaultValueBoolean bug

* OMG I think I finally fixed MySQL

* Remove Java source file and prep-deps code

* Remove two more references to bin/prep.sh

* Minor cleanup

* Revert unneeded changes

* Fix busted indentation

* Don't search inside java/ anymore since it's G-O-N-E

* Appease the namespace linter

* Update src/metabase/db/liquibase/h2.clj