Solve multi word CI variables not quoted properly

ie. fix below quoting issue:

```
kubectl create secret -n project-with-autodevops-900057eb1ce34399-77 \
  generic production-secret \
  '--from-literal=OPTIONAL_MESSAGE=You' can see this secret \
  -o yaml --dry-run
```

With fix, it should be generating:

```
kubectl create secret -n project-with-autodevops-900057eb1ce34399-77 \
  generic production-secret \
  --from-literal 'OPTIONAL_MESSAGE=You can see this secret' \
  -o yaml --dry-run
```

Call via bash -c, instead of assuming bash

The shell is /bin/sh, so we cannot asssume bash. Hence we use `bash -c`

bash is installed for deploy jobs in a prior step

lib/gitlab/ci/templates/Auto-DevOps.gitlab-ci.yml

@@ -595,13 +595,44 @@ rollout 100%:
     fi
   }
 
-  # Finds any variables prefixed with `K8S_SECRET_`, and exports them as the
-  # global $K8S_VARIABLES with prefix removed.
-  function extract_prefixed_variables() {
-    prefix="K8S_SECRET_"
-    k8s_variables=$(env | (grep "^${prefix}" || [[ $? == 1 ]]) | sed "s/^${prefix}//")
-
-    export K8S_VARIABLES=$k8s_variables
+  # Extracts variables prefixed with K8S_SECRET_
+  # and creates a Kubernetes secret.
+  #
+  # e.g. if we have the following vars
+  #   K8S_SECRET_A=value1
+  #   K8S_SECRET_B=multi\ word\ value
+  #
+  # Then we get:
+  #   --from-literal K8S_SECRET_A=value1 --from-literal 'K8S_SECRET_B=multi word value'
+  #
+  # NOTE: We set IFS as we need to split by newline so that we can loop through
+  # multi word variables correctly.
+  function create_application_secret() {
+    bash -c '
+      function extract_prefixed_variables() {
+        prefix="K8S_SECRET_"
+        k8s_variables=$(env | (grep "^${prefix}" || [[ $? == 1 ]]))
+
+        export K8S_VARIABLES=$k8s_variables
+      }
+
+      function create_secret() {
+        local IFS=$(echo -en "\n\b")
+        for k8s_variable in $K8S_VARIABLES; do
+          param="${k8s_variable#K8S_SECRET_}"
+
+          fromLiteralArgs+=("--from-literal")
+          fromLiteralArgs+=("${param}")
+        done
+
+        kubectl create secret \
+          -n "$KUBE_NAMESPACE" generic "$APPLICATION_SECRET_NAME" ${fromLiteralArgs[@]} -o yaml \
+          --dry-run | kubectl replace -n "$KUBE_NAMESPACE" --force -f -
+      }
+
+      extract_prefixed_variables
+      create_secret
+    '
   }
 
   function deploy() {
@@ -629,22 +660,8 @@ rollout 100%:
       secret_name=''
     fi
 
-    extract_prefixed_variables
-    if [[ -n "$K8S_VARIABLES" ]]; then
-      echo "Prefixed CI variables found, creating secret..."
-      application_secret_name="${name}-secret"
-      fromLiteralArgs=""
-
-      for k8s_variable in ${K8S_VARIABLES}; do
-        fromLiteralArgs="${fromLiteralArgs:+${fromLiteralArgs} }--from-literal=${k8s_variable}"
-      done
-
-      # We want fromLiteralArgs to be interpreted as args, so don't quote it!
-      kubectl create secret -n "$KUBE_NAMESPACE" \
-        generic "$application_secret_name" \
-        ${fromLiteralArgs} \
-        -o yaml --dry-run | kubectl replace -n "$KUBE_NAMESPACE" --force -f -
-    fi
+    export APPLICATION_SECRET_NAME="${name}-secret"
+    create_application_secret
 
     if [[ -n "$DB_INITIALIZE" && -z "$(helm ls -q "^$name$")" ]]; then
       echo "Deploying first release with database initialization..."
@@ -658,7 +675,7 @@ rollout 100%:
         --set image.secrets[0].name="$secret_name" \
         --set application.track="$track" \
         --set application.database_url="$DATABASE_URL" \
-        --set application.secretName="$application_secret_name" \
+        --set application.secretName="$APPLICATION_SECRET_NAME" \
         --set service.url="$CI_ENVIRONMENT_URL" \
         --set replicaCount="$replicas" \
         --set postgresql.enabled="$postgres_enabled" \
@@ -691,7 +708,7 @@ rollout 100%:
         --set image.secrets[0].name="$secret_name" \
         --set application.track="$track" \
         --set application.database_url="$DATABASE_URL" \
-        --set application.secretName="$application_secret_name" \
+        --set application.secretName="$APPLICATION_SECRET_NAME" \
         --set service.url="$CI_ENVIRONMENT_URL" \
         --set replicaCount="$replicas" \
         --set postgresql.enabled="$postgres_enabled" \