Add alpha flavour and different strings so testers can differentiate builds

.gitlab-ci.yml

@@ -119,7 +119,7 @@ build alpha:
     - large
   script:
     - ./gradlew clean
-    - ./gradlew assembleProductionRelease
+    - ./gradlew assembleAlphaRelease
   artifacts:
     expire_in: 3 week
     paths:

app/build.gradle.kts

@@ -142,6 +142,9 @@ android(
         register("beta") {
             applicationId = "ch.protonmail.android.beta"
         }
+        register("alpha") {
+            applicationId = "ch.protonmail.android.alpha"
+        }
     }
 
     buildTypes {

app/src/alpha/res/values/strings.xml

@@ -0,0 +1,28 @@
+<!--
+  ~ Copyright (c) 2020 Proton Technologies AG
+  ~
+  ~ This file is part of ProtonMail.
+  ~
+  ~ ProtonMail is free software: you can redistribute it and/or modify
+  ~ it under the terms of the GNU General Public License as published by
+  ~ the Free Software Foundation, either version 3 of the License, or
+  ~ (at your option) any later version.
+  ~
+  ~ ProtonMail is distributed in the hope that it will be useful,
+  ~ but WITHOUT ANY WARRANTY; without even the implied warranty of
+  ~ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+  ~ GNU General Public License for more details.
+  ~
+  ~ You should have received a copy of the GNU General Public License
+  ~ along with ProtonMail. If not, see https://www.gnu.org/licenses/.
+  -->
+
+<resources xmlns:tools="http://schemas.android.com/tools" tools:ignore="MissingTranslation">
+
+    <!-- region All -->
+    <string name="x_app_version_name_code">ProtonMail %s (%d) Alpha</string>
+    <!-- endregion -->
+
+    <string name="app_version_code" translatable="false">%1$s (%2$d) Alpha</string>
+
+</resources>