Disable inputs in configuration screen for non-owners

Users not owning the repository could enter data in the repository
configuration. While saving them failed, this could lead to confusion.

Change-Id: I50cdb51ccd08b0581b102d672b3dc2a610d6777b
diff --git a/src/main/resources/static/gr-reviewers-by-blame-config.html b/src/main/resources/static/gr-reviewers-by-blame-config.html
index 01269b9..3cdca3e 100644
--- a/src/main/resources/static/gr-reviewers-by-blame-config.html
+++ b/src/main/resources/static/gr-reviewers-by-blame-config.html
@@ -30,7 +30,8 @@
             <input id="ignoreFileRegEx"
                    value="{{_changedConfig.ignoreFileRegEx.value::input}}"
                    type="text"
-                   on-input="_handlePrefsChanged">
+                   on-input="_handlePrefsChanged"
+                   disabled$="[[readOnly]]">
           </iron-input>
         </span>
         <span class="value">
@@ -44,7 +45,8 @@
             <input id="ignoreSubjectRegEx"
                    value="{{_changedConfig.ignoreSubjectRegEx.value::input}}"
                    type="text"
-                   on-input="_handlePrefsChanged">
+                   on-input="_handlePrefsChanged"
+                   disabled$="[[readOnly]]">
           </iron-input>
         </span>
         <span class="value">
@@ -61,7 +63,8 @@
                    allowed-pattern="[0-9]"
                    type="number"
                    on-keypress="_handlePrefsChanged"
-                   on-change="_handlePrefsChanged">
+                   on-change="_handlePrefsChanged"
+                   disabled$="[[readOnly]]">
           </iron-input>
         </span>
         <span class="value">
diff --git a/src/main/resources/static/gr-reviewers-by-blame-config.js b/src/main/resources/static/gr-reviewers-by-blame-config.js
index d64b316..5957f94 100644
--- a/src/main/resources/static/gr-reviewers-by-blame-config.js
+++ b/src/main/resources/static/gr-reviewers-by-blame-config.js
@@ -27,6 +27,10 @@
         value: false,
       },
       _projectRestApi: Object,
+      readOnly: {
+        type: Boolean,
+        value: true,
+      },
     },
 
     attached() {