fix 457 Support for Bearer Auth (#1930)

* fix #457 by introducing an HttpBearerAuth object

See https://github.com/OpenAPITools/openapi-generator/issues/457
Also https://github.com/OpenAPITools/openapi-generator/issues/1446 for typescript, https://github.com/OpenAPITools/openapi-generator/issues/1577 for python

Specs defined as follows currently generate BasicAuth and send an "Authorization: Basic [base64Encode(username + ":" + password)]" header
    components:
      securitySchemes:
        bearer:
          type: http
          scheme: bearer

This change will generate code which uses a new HttpBearerAuth class, which will send a "Authorization: [scheme] [accessToken]" header.
This change is slightly larger and more impactful than simply using OAuth for bearerBearer, but it allows for scheme values other than bearer.

This fix was enabled by the recent commit of 80ca67cfda

This PR is an alternative to https://github.com/OpenAPITools/openapi-generator/pull/1972

* update petstore samples

* Update HttpBearerAuth mustache templates and samples

* correct the expected number of generated java client files

* update the retrofit2 HttpBearerAuth template and samples

* Add resttemplate-specific HttpBearerAuth mustache and samples

* add vertx-specific HttpBearerAuth template and samples

* add java webclient-specific HttpBearerAuth template and samples

samples/client/petstore/java/okhttp-gson/src/main/java/org/openapitools/client/auth/HttpBearerAuth.java

@@ -0,0 +1,56 @@
+/*
+ * OpenAPI Petstore
+ * This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\
+ *
+ * OpenAPI spec version: 1.0.0
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+
+package org.openapitools.client.auth;
+
+import org.openapitools.client.Pair;
+
+import java.util.Map;
+import java.util.List;
+
+
+public class HttpBearerAuth implements Authentication {
+  private final String scheme;
+  private String bearerToken;
+
+  public HttpBearerAuth(String scheme) {
+    this.scheme = scheme;
+  }
+
+  /**
+   * Gets the token, which together with the scheme, will be sent as the value of the Authorization header.
+   */
+  public String getBearerToken() {
+    return bearerToken;
+  }
+
+  /**
+   * Sets the token, which together with the scheme, will be sent as the value of the Authorization header.
+   */
+  public void setBearerToken(String bearerToken) {
+    this.bearerToken = bearerToken;
+  }
+
+  @Override
+  public void applyToParams(List<Pair> queryParams, Map<String, String> headerParams) {
+    if(bearerToken == null) {
+      return;
+    }
+
+    headerParams.put("Authorization", (scheme != null ? upperCaseBearer(scheme) + " " : "") + bearerToken);
+  }
+
+  private static String upperCaseBearer(String scheme) {
+    return ("bearer".equalsIgnoreCase(scheme)) ? "Bearer" : scheme;
+  }
+}