For Ansible-based Operator, add .gitignore file which was missing. (#…

…3806)

**Description of the change:**
- For Ansible-based Operator, add `.gitignore` file which was missing.

**Motivation for the change:**
- Following the good practices, users should not commit the binaries that are added to the bin/ dir. 
- Keep all projects/types following the same standard.

changelog/fragments/ansible-gitignore.yaml

@@ -0,0 +1,16 @@
+# entries is a list of entries to include in
+# release notes and/or the migration guide
+entries:
+  - description: >
+      For Ansible-based Operator, add `.gitignore` file.
+
+    # kind is one of:
+    # - addition
+    # - change
+    # - deprecation
+    # - removal
+    # - bugfix
+    kind: "addition"
+
+    # Is this a breaking change?
+    breaking: false

internal/plugins/ansible/v1/scaffolds/init.go

@@ -80,6 +80,7 @@ func (s *initScaffolder) scaffold() error {
 	return machinery.NewScaffold().Execute(
 		s.newUniverse(),
 		&templates.Dockerfile{},
+		&templates.GitIgnore{},
 		&templates.RequirementsYml{},
 		&templates.Watches{},
 

internal/plugins/ansible/v1/scaffolds/internal/templates/gitignore.go

@@ -0,0 +1,56 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+Modifications copyright 2020 The Operator-SDK Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package templates
+
+import (
+	"sigs.k8s.io/kubebuilder/pkg/model/file"
+)
+
+var _ file.Template = &GitIgnore{}
+
+// GitIgnore scaffolds the .gitignore file
+type GitIgnore struct {
+	file.TemplateMixin
+}
+
+// SetTemplateDefaults implements input.Template
+func (f *GitIgnore) SetTemplateDefaults() error {
+	if f.Path == "" {
+		f.Path = ".gitignore"
+	}
+
+	f.TemplateBody = gitignoreTemplate
+
+	return nil
+}
+
+const gitignoreTemplate = `
+# Binaries for programs and plugins
+*.exe
+*.exe~
+*.dll
+*.so
+*.dylib
+bin
+
+# editor and IDE paraphernalia
+.idea
+*.swp
+*.swo
+*~
+`