Enforce lint cleanliness when building (#3363)

* Enforce lint cleanliness when building

The volume of lintable issues is growing. To stem the tide:

1. Add `app/lint-baseline.xml`, which contains the current set of lint issues.
   Any issue appearing here will not cause the build to fail.

2. Move lint configuration settings in to `lint.xml`.

3. Update the lint configuration so that any issue (i.e., any issue not
   in lint-baseline.xml) causes a build failure.

4. Add the lint tasks as depedency when assembling an APK, to ensure the
   lint checks are run.

* lint: Convert launcher images to webp

* Move lint.xml location

* Don't lint when assembling

* Update baseline

app/build.gradle

@@ -58,8 +58,12 @@ android {
     }
 
     lint {
-        disable 'MissingTranslation'
+        lintConfig file("lint.xml")
+        // Regenerate by deleting app/lint-baseline.xml, then run:
+        //   ./gradlew lintBlueDebug
+        baseline = file("lint-baseline.xml")
     }
+
     buildFeatures {
         buildConfig true
         resValues true

app/lint.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!--
+  ~ Copyright 2023 Tusky Contributors
+  ~
+  ~ This file is a part of Tusky.
+  ~
+  ~ This program 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.
+  ~
+  ~ Tusky 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 Tusky; if not,
+  ~ see <http://www.gnu.org/licenses>.
+  -->
+
+<lint>
+    <!-- Missing translations are OK -->
+    <issue id="MissingTranslation" severity="ignore" />
+
+    <!-- Duplicate strings are OK. This can happen when e.g., "favourite" appears as both
+         a noun and a verb -->
+    <issue id="DuplicateStrings" severity="ignore" />
+
+    <!-- Ensure we are warned about errors in the baseline -->
+    <issue id="LintBaseline" severity="warning" />
+
+    <!-- Mark all other lint issues as errors -->
+    <issue id="all" severity="error" />
+</lint>