adds [Performance Testing] Nightly Build Job (#114042)

Adds auto and manual performance tests

If "ITERATION_COUNT_ENV" exist in build job:
- Auto Mode: Checks "ITERATION_COUNT_ENV",
- Manual Mode: Waits for user input,
use provided value to run "n" number of performance tests on parallel
- Sends slack notifications when pipeline finished

.buildkite/pipelines/performance/nightly.yml

@@ -0,0 +1,35 @@
+steps:
+  - block: ":gear: Performance Tests Configuration"
+    prompt: "Fill out the details for performance test"
+    fields:
+      - text: ":arrows_counterclockwise: Iterations"
+        key: "performance-test-iteration-count"
+        hint: "How many times you want to run tests? "
+        required: true
+    if: build.env('ITERATION_COUNT_ENV') == null
+
+  - label: ":male-mechanic::skin-tone-2: Pre-Build"
+    command: .buildkite/scripts/lifecycle/pre_build.sh
+
+  - wait
+
+  - label: ":factory_worker: Build Kibana Distribution and Plugins"
+    command: .buildkite/scripts/steps/build_kibana.sh
+    agents:
+      queue: c2-16
+    key: build
+
+  - label: ":muscle: Performance Tests"
+    command: .buildkite/scripts/steps/functional/performance.sh
+    agents:
+      queue: ci-group-6
+    depends_on: build
+    concurrency: 50
+    concurrency_group: 'performance-test-group'
+
+  - wait: ~
+    continue_on_failure: true
+
+  - label: ":male_superhero::skin-tone-2: Post-Build"
+    command: .buildkite/scripts/lifecycle/post_build.sh
+