Cleanup Transaction Manager Launcher

[prd-fox]

Background server threads mean the process will not terminate until required, and even then it will not exit with a code of 0. Therefore, there is no need to have the CountdownLatch waiting for termination of the main thread.

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if (!cliResult.getConfig().isPresent() && cliResult.isSuppressStartup()) {
    System.exit(cliResult.getStatus());
}

was impossible to get into, due to a prior check for cliResult.isSuppressStartup() causing a System.exit if true. It also doesn't make sense as if this check could be entered, the only valid exit code is 0, so this has been removed entirely. All operations that don't create a config object should set the suppressed startup flag.

[codecov-io]

Codecov Report

Merging #660 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff            @@
##             master    #660   +/-   ##
========================================
  Coverage      99.5%   99.5%           
  Complexity     1836    1836           
========================================
  Files           281     281           
  Lines          5487    5487           
  Branches        268     268           
========================================
  Hits           5460    5460           
  Misses            5       5           
  Partials         22      22

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