Move deployment configuration templates to be in files (#709)

**What this PR does / why we need it**:

**Which issue(s) this PR fixes**:

Fixes #

**Does this PR introduce a user-facing change?**:
<!--
If no, just write "NONE" in the release-note block below.
-->
```release-note
NONE
```

/cc @nakabonne 
This PR was merged by Kapetanios.

BUILD.bazel

@@ -35,7 +35,7 @@ buildifier(
 
 genrule(
     name = "copy_piped",
-    srcs = ["//cmd/piped"],
+    srcs = ["//cmd/piped:piped"],
     outs = ["piped"],
     cmd = "cp $< $@",
 )
@@ -56,3 +56,4 @@ genrule(
 # gazelle:exclude pkg/model/project.pb.validate.go
 # gazelle:exclude pkg/model/role.pb.validate.go
 # gazelle:exclude pkg/model/user.pb.validate.go
+# gazelle:exclude pkg/app/api/api/deployment_config_templates.embed.go

pkg/app/api/api/BUILD.bazel

@@ -7,6 +7,7 @@ go_library(
         "fake_web_api.go",
         "piped_api.go",
         "web_api.go",
+        ":deployment_config_templates.embed", #keep
     ],
     importpath = "github.com/pipe-cd/pipe/pkg/app/api/api",
     visibility = ["//visibility:public"],
@@ -35,3 +36,15 @@ go_test(
     embed = [":go_default_library"],
     deps = ["//pkg/app/api/service/webservice:go_default_library"],
 )
+
+load("@io_bazel_rules_go//go:def.bzl", "go_embed_data")
+
+go_embed_data(
+    name = "deployment_config_templates.embed",
+    srcs = glob(["deploymentconfigtemplates/*"]),
+    flatten = True,
+    package = "api",
+    string = True,
+    var = "DeploymentConfigTemplates",
+    visibility = ["//visibility:public"],
+)

pkg/app/api/api/deployment_config_templates.go

@@ -23,75 +23,26 @@ var (
 	k8sDeploymentConfigTemplates = []*webservice.DeploymentConfigTemplate{
 		{
 			ApplicationKind: model.ApplicationKind_KUBERNETES,
-			Name:            "Canary Deployment",
+			Name:            "Simple",
+			Labels:          []webservice.DeploymentConfigTemplateLabel{},
+			Content:         DeploymentConfigTemplates["KubernetesSimple"],
+		},
+		{
+			ApplicationKind: model.ApplicationKind_KUBERNETES,
+			Name:            "Canary",
 			Labels:          []webservice.DeploymentConfigTemplateLabel{webservice.DeploymentConfigTemplateLabel_CANARY},
-			Content:         k8sCanaryDeploymentConfigTemplate,
+			Content:         DeploymentConfigTemplates["KubernetesCanary"],
 		},
 		{
 			ApplicationKind: model.ApplicationKind_KUBERNETES,
-			Name:            "Blue/Green Deployment",
+			Name:            "Blue/Green",
 			Labels:          []webservice.DeploymentConfigTemplateLabel{webservice.DeploymentConfigTemplateLabel_BLUE_GREEN},
-			Content:         k8sBluegreenDeploymentConfigTemplate,
+			Content:         DeploymentConfigTemplates["KubernetesBlueGreen"],
 		},
 	}
+
 	terraformDeploymentConfigTemplates  = []*webservice.DeploymentConfigTemplate{}
 	crossplaneDeploymentConfigTemplates = []*webservice.DeploymentConfigTemplate{}
 	lambdaDeploymentConfigTemplates     = []*webservice.DeploymentConfigTemplate{}
 	cloudrunDeploymentConfigTemplates   = []*webservice.DeploymentConfigTemplate{}
 )
-
-const (
-	k8sCanaryDeploymentConfigTemplate = `
-apiVersion: pipecd.dev/v1beta1
-kind: KubernetesApp
-spec:
-  commitMatcher:
-    sync: "^Revert"
-  pipeline:
-    stages:
-      # Deploy the workloads of CANARY variant. In this case, the number of
-      # workload replicas of CANARY variant is 10% of the replicas number of PRIMARY variant.
-      - name: K8S_CANARY_ROLLOUT
-        with:
-          replicas: 10%
-      # Wait 10 seconds before going to the next stage.
-      - name: WAIT
-        with:
-          duration: 10s
-      # Update the workload of PRIMARY variant to the new version.
-      - name: K8S_PRIMARY_ROLLOUT
-      # Destroy all workloads of CANARY variant.
-      - name: K8S_CANARY_CLEAN
-`
-
-	k8sBluegreenDeploymentConfigTemplate = `
-apiVersion: pipecd.dev/v1beta1
-kind: KubernetesApp
-spec:
-  pipeline:
-    stages:
-      # Deploy the workloads of CANARY variant. In this case, the number of
-      # workload replicas of CANARY variant is the same with PRIMARY variant.
-      - name: K8S_CANARY_ROLLOUT
-        with:
-          replicas: 100%
-      # The percentage of traffic each variant should receive.
-      # In this case, CANARY variant will receive all of the traffic.
-      - name: K8S_TRAFFIC_ROUTING
-        with:
-          all: canary
-      - name: WAIT_APPROVAL
-      # Update the workload of PRIMARY variant to the new version.
-      - name: K8S_PRIMARY_ROLLOUT
-      # The percentage of traffic each variant should receive.
-      # In this case, PRIMARY variant will receive all of the traffic.
-      - name: K8S_TRAFFIC_ROUTING
-        with:
-          primary: 100
-      # Destroy all workloads of CANARY variant.
-      - name: K8S_CANARY_CLEAN
-  # This example is not using service mesh.
-  trafficSplit:
-    method: pod
-`
-)

pkg/app/api/api/deploymentconfigtemplates/KubernetesBlueGreen

@@ -0,0 +1,32 @@
+# Deploy progressively with bluegreen stragegy.
+apiVersion: pipecd.dev/v1beta1
+kind: KubernetesApp
+spec:
+  pipeline:
+    stages:
+      # Deploy the workloads of CANARY variant. In this case, the number of
+      # workload replicas of CANARY variant is the same with PRIMARY variant.
+      - name: K8S_CANARY_ROLLOUT
+        with:
+          replicas: 100%
+
+      # The percentage of traffic each variant should receive.
+      # In this case, CANARY variant will receive all of the traffic.
+      - name: K8S_TRAFFIC_ROUTING
+        with:
+          all: canary
+
+      # Wait a manual approval from a developer on web.
+      - name: WAIT_APPROVAL
+
+      # Update the workload of PRIMARY variant to the new version.
+      - name: K8S_PRIMARY_ROLLOUT
+
+      # The percentage of traffic each variant should receive.
+      # In this case, PRIMARY variant will receive all of the traffic.
+      - name: K8S_TRAFFIC_ROUTING
+        with:
+          primary: 100
+
+      # Destroy all workloads of CANARY variant.
+      - name: K8S_CANARY_CLEAN

pkg/app/api/api/deploymentconfigtemplates/KubernetesCanary

@@ -0,0 +1,20 @@
+# Deploy progressively with canary stragegy.
+apiVersion: pipecd.dev/v1beta1
+kind: KubernetesApp
+spec:
+  pipeline:
+    stages:
+      # Deploy the workloads of CANARY variant. In this case, the number of
+      # workload replicas of CANARY variant is 10% of the replicas number of PRIMARY variant.
+      - name: K8S_CANARY_ROLLOUT
+        with:
+          replicas: 10%
+
+      # Wait a manual approval from a developer on web.
+      - name: WAIT_APPROVAL
+
+      # Update the workload of PRIMARY variant to the new version.
+      - name: K8S_PRIMARY_ROLLOUT
+
+      # Destroy all workloads of CANARY variant.
+      - name: K8S_CANARY_CLEAN

pkg/app/api/api/deploymentconfigtemplates/KubernetesSimple

@@ -0,0 +1,4 @@
+# Deploy plain-yaml manifests placing in the application configuration directory without specifying pipeline.
+apiVersion: pipecd.dev/v1beta1
+kind: KubernetesApp
+spec: