tests: Adjust parallel tests

- The usual serial to parallel test conversion to utilize the `setup.bash` common setup structure, and adding a `TEST_PREFIX` var for each test case to leverage.
- Standardize on parallel test naming conventions for variables / values.
- More consistent use of `bash -c` instead of `/bin/bash -c` or `/bin/sh -c`.
- Using the `_run_in_container` helper instead of `run docker exec ${CONTAINER_NAME}`.
- Updates tests to use the `check_if_process_is_running` helper.

---

chore: Revise inline docs for the `ssl_letsencrypt` test

- Moves the override to be in closer proximity to the `initial_setup` call, and better communicates the intent to override.
- Removes top comment block that is no longer providing value or correct information to maintainers.
- Revised `acme.json` test case inline doc comments.

test/tests/parallel/set3/dovecot_inet_protocol.bats

@@ -2,9 +2,14 @@ load "${REPOSITORY_ROOT}/test/helper/setup"
 load "${REPOSITORY_ROOT}/test/helper/common"
 
 TEST_NAME_PREFIX='Dovecot protocols:'
+CONTAINER1_NAME='dms-test_dovecot_protocols_all'
+CONTAINER2_NAME='dms-test_dovecot_protocols_ipv4'
+CONTAINER3_NAME='dms-test_dovecot_protocols_ipv6'
+
+function teardown() { _default_teardown ; }
 
 @test "${TEST_NAME_PREFIX} dual-stack IP configuration" {
-  local CONTAINER_NAME='dms-test-dovecot_protocols_all'
+  export CONTAINER_NAME=${CONTAINER1_NAME}
   local CUSTOM_SETUP_ARGUMENTS=(--env DOVECOT_INET_PROTOCOLS=)
 
   init_with_defaults
@@ -13,12 +18,10 @@ TEST_NAME_PREFIX='Dovecot protocols:'
   _run_in_container grep '^#listen = \*, ::' /etc/dovecot/dovecot.conf
   assert_success
   assert_output '#listen = *, ::'
-
-  docker rm -f "${CONTAINER_NAME}"
 }
 
 @test "${TEST_NAME_PREFIX} IPv4 configuration" {
-  local CONTAINER_NAME='dms-test-dovecot_protocols_ipv4'
+  export CONTAINER_NAME=${CONTAINER2_NAME}
   local CUSTOM_SETUP_ARGUMENTS=(--env DOVECOT_INET_PROTOCOLS=ipv4)
 
   init_with_defaults
@@ -27,12 +30,10 @@ TEST_NAME_PREFIX='Dovecot protocols:'
   _run_in_container grep '^listen = \*$' /etc/dovecot/dovecot.conf
   assert_success
   assert_output 'listen = *'
-
-  docker rm -f "${CONTAINER_NAME}"
 }
 
 @test "${TEST_NAME_PREFIX} IPv6 configuration" {
-  local CONTAINER_NAME='dms-test-dovecot_protocols_ipv6'
+  export CONTAINER_NAME=${CONTAINER3_NAME}
   local CUSTOM_SETUP_ARGUMENTS=(--env DOVECOT_INET_PROTOCOLS=ipv6)
 
   init_with_defaults
@@ -41,6 +42,4 @@ TEST_NAME_PREFIX='Dovecot protocols:'
   _run_in_container grep '^listen = \[::\]$' /etc/dovecot/dovecot.conf
   assert_success
   assert_output 'listen = [::]'
-
-  docker rm -f "${CONTAINER_NAME}"
 }