The java version checker requires being written with java 7 APIs.
In order to use java 8 apis in other launcher utilities, this commit
moves the java version checker back to its own jar.

* elastic/master:
  [DOCS] Removes out-dated x-pack/docs/en/index.asciidoc
  [DOCS] Removes redundant index.asciidoc files (elastic#30707)
  [TEST] Reduce forecast overflow to disk test memory limit (elastic#30727)
  Plugins: Remove meta plugins (elastic#30670)
  [DOCS] Moves X-Pack configurationg pages in table of contents (elastic#30702)
  TEST: Add engine log to testCorruptFileThenSnapshotAndRestore
  [ML][TEST] Fix bucket count assertion in ModelPlotsIT (elastic#30717)
  [ML][TEST] Make AutodetectMemoryLimitIT less fragile (elastic#30716)
  Default copy settings to true and deprecate on the REST layer (elastic#30598)
  [Build] Add test admin when starting gradle run with trial license and
  This implementation lazily (on 1st forecast request) checks for available diskspace and creates a subfolder for storing data outside of Lucene indexes, but as part of the ES data paths.
  Tests: Fail if test watches could not be triggered (elastic#30392)
  [ML] add version information in case of crash of native ML process (elastic#30674)
  Make TransportClusterStateAction abide to our style (elastic#30697)
  Change required version for Get Settings transport API changes to 6.4.0 (elastic#30706)

…ecker

* elastic/master: (309 commits)
  [test] add fix for rare virtualbox error (elastic#31212)
  Move default location of dependencies report (elastic#31228)
  Remove dependencies report task dependencies (elastic#31227)
  Add recognition of MPL 2.0 (elastic#31226)
  Fix unknown licenses (elastic#31223)
  Remove version from license file name for GCS SDK (elastic#31221)
  Fully encapsulate LocalCheckpointTracker inside of the engine (elastic#31213)
  [DOCS] Added 'fail_on_unsupported_field' param to MLT. Closes elastic#28008 (elastic#31160)
  Add licenses for transport-nio (elastic#31218)
  Remove DocumentFieldMappers#simpleMatchToFullName. (elastic#31041)
  Allow to trim all ops above a certain seq# with a term lower than X, post backport fix (elastic#31211)
  Compliant SAML Response destination check (elastic#31175)
  Remove DocumentFieldMappers#smartNameFieldMapper, as it is no longer needed. (elastic#31018)
  Remove extraneous references to 'tokenized' in the mapper code. (elastic#31010)
  Allow to trim all ops above a certain seq# with a term lower than X (elastic#30176)
  SQL: Make a single JDBC driver jar (elastic#31012)
  Enhance license detection for various licenses (elastic#31198)
  [DOCS] Add note about long-lived idle connections (elastic#30990)
  Move number of language analyzers to analysis-common module (elastic#31143)
  Default max concurrent search req. numNodes * 5 (elastic#31171)
  ...