Snort3 demo is having trouble running on my baseline Snort environment Krakatoa

This PR introduces a few small cleanups that improve portability of the snort3_demo environment.

My intention is to use the snort3_demo as the testing framework for Snort3 in all of my environments (Open and Private repos).

Prior to my changes running run_tests.sh failed 85 of 85 test

After my changes, the tests pass 78 of 85 tests

Total = 85, Pass = 78, Fail = 7, Skip = 0

My primary commit message follows

snort3_demo: Refactor run_test.sh script

This commit refactors the snort3_demo repository so that it can be executed
somewhat more portably, and ideally feels a bit more comfortable to the user.

These changes make one big assumption, namely:

• snort and libdaq are installed to the default PREFIX directory
  (/usr/local).

  With this assumption made, the user is no longer responsible for
  specifying the install location for "snorty", i.e., argv[1] will
  now specify the path of tests to execute.

  NOTICE: If necessary, I will provide an override in the form of an
  environment variable to restore specifying an alternate
  install PREFIX.

Now argv[1] specifices the path to the "top" directory to search for,
and run tests from. The following commands are now all valid:

• ./run_tests.sh tests/ips_options

  Runs all tests under "tests/ips_options/*"

• ./run_tests.sh tests/ips_options/so_and_soid

  Runs the singular test under "tests/ips_options/so_and_soid/"

• ./run_tests.sh tests/ips_options/so_and_soid/test.bats

  Identical to the previous exmaple, runs the singular test under
  "tests/ips_options/so_and_soid/"

• ./run_tests.sh /root/alternate-path/some-private/integration-tests/

  Runs all the tests under the user specified external directory.

The last major refactor to the script is the way which tests are
"searched and exected". Previously, the run_tests.sh used find to
create a singular long command line argument of "directories" containing
the "tests.bat" script, passing it as an argument to a loop defined in
the same file.

The script is now chagned to use find -exec run_one, which is
functionally equivalent, but is now future proofed from maxing out
command line arguments, or size of a command line in the given shell.

NOTICE: Acceptance of this PR will surely result in further refactorying
to make the environment more portable still.