Do not test with Kafka 2.x (#6427)

## Which problem is this PR solving?
- Resolves #3068
- According to https://endoflife.date/apache-kafka the support for Kafka
2.x ended 2yrs ago. There is no reason to waste CI resources testing
against it.
- Our documentation only mentions 3.x
https://www.jaegertracing.io/docs/2.1/kafka/

## Description of the changes
- Remove Kafka 2.x from the test matrix
- Remove the corresponding docker-compose file

## How was this change tested?
- CI

---------

Signed-off-by: Yuri Shkuro <[email protected]>

.github/workflows/ci-e2e-kafka.yml

@@ -18,7 +18,7 @@ jobs:
       fail-fast: false
       matrix:
         jaeger-version: [v1, v2]
-        kafka-version: ["3.x", "2.x"]
+        kafka-version: ["3.x"]
     name: kafka ${{matrix.kafka-version }} ${{ matrix.jaeger-version }}
     steps:
     - name: Harden Runner

scripts/kafka-integration-test.sh

@@ -6,28 +6,21 @@
 set -euf -o pipefail
 
 compose_file=""
-jaeger_version=""
-kafka_version=""
+jaeger_version="v2"
+kafka_version="v3"
 manage_kafka="true"
 success="false"
 
 usage() {
-  echo "Usage: $0 [-K] -j <jaeger_version> -v <kafka_version>"
-  echo "  -K: do not start or stop Kafka container (useful for local testing)"
-  echo "  -j: major version of Jaeger to test (v1|v2)"
-  echo "  -v: kafka major version (3.x|2.x)"
+  echo "Usage: $0 [-S] [-j <jaeger_version>] [-v <kafka_version>]"
+  echo "  -S: 'no storage' - do not start or stop Kafka container (useful for local testing)"
+  echo "  -j: major version of Jaeger to test (v1|v2); default: v2"
+  echo "  -v: kafka major version (3.x); default: 3.x"
   exit 1
 }
 
-check_arg() {
-  if [ ! $# -eq 3 ]; then
-      echo "ERROR: need exactly three arguments"
-      usage
-    fi
-}
-
 parse_args() {
-  while getopts "j:v:Kh" opt; do
+  while getopts "j:v:Sh" opt; do
     case "${opt}" in
     j)
       jaeger_version=${OPTARG}
@@ -46,7 +39,7 @@ parse_args() {
         ;;
       esac
       ;;
-    K)
+    S)
       manage_kafka="false"
       ;;
     *)
@@ -61,7 +54,6 @@ parse_args() {
   compose_file="docker-compose/kafka/${kafka_version}/docker-compose.yml"
 }
 
-
 setup_kafka() {
   echo "Starting Kafka using Docker Compose..."
   docker compose -f "${compose_file}" up -d kafka