Support resolution switching (#597)

## Description
Adds a settings for automatic resolution switching. When enabled, the
app tries to output content at the video stream's resolution.

For example, if playing 1080p content on a 4K TV, the actual output by
the Android TV device will be 1080p.

This works in hand-in-hand with automatic refresh rate switching. So
enabling both allows for the output to match both refresh rate and
content resolution. Outputting the best refresh rate is preferred over
best resolution.

Also, shows the current display mode in the playback debug info.

### Related issues
Closes #428 
Fixes #531

app/src/test/java/com/github/damontecres/wholphin/test/TestDisplayModeChoice.kt

@@ -0,0 +1,124 @@
+package com.github.damontecres.wholphin.test
+
+import com.github.damontecres.wholphin.services.DisplayMode
+import com.github.damontecres.wholphin.services.RefreshRateService
+import org.junit.Assert
+import org.junit.Test
+
+class TestDisplayModeChoice {
+    companion object {
+        val HD_60 = DisplayMode(0, 1920, 1080, 60f)
+        val HD_30 = DisplayMode(1, 1920, 1080, 30f)
+        val HD_24 = DisplayMode(2, 1920, 1080, 24f)
+
+        val UHD_60 = DisplayMode(3, 3840, 2160, 60f)
+        val UHD_30 = DisplayMode(4, 3840, 2160, 30f)
+        val UHD_24 = DisplayMode(5, 3840, 2160, 24f)
+
+        val ALL_MODES = listOf(UHD_24, UHD_30, UHD_60, HD_24, HD_30, HD_60)
+    }
+
+    @Test
+    fun test1() {
+        val streamWidth = 1920
+        val streamHeight = 1080
+        val streamRealFrameRate = 60f
+        val result =
+            RefreshRateService.findDisplayMode(
+                displayModes = ALL_MODES,
+                streamWidth = streamWidth,
+                streamHeight = streamHeight,
+                targetFrameRate = streamRealFrameRate,
+                refreshRateSwitch = true,
+                resolutionSwitch = false,
+            )
+        Assert.assertEquals(3, result?.modeId)
+    }
+
+    @Test
+    fun test2() {
+        val streamWidth = 1920
+        val streamHeight = 1080
+        val streamRealFrameRate = 60f
+        val result =
+            RefreshRateService.findDisplayMode(
+                displayModes = ALL_MODES,
+                streamWidth = streamWidth,
+                streamHeight = streamHeight,
+                targetFrameRate = streamRealFrameRate,
+                refreshRateSwitch = true,
+                resolutionSwitch = true,
+            )
+        Assert.assertEquals(0, result?.modeId)
+    }
+
+    @Test
+    fun test3() {
+        val streamWidth = 1920
+        val streamHeight = 1080
+        val streamRealFrameRate = 30f
+        val result =
+            RefreshRateService.findDisplayMode(
+                displayModes = ALL_MODES,
+                streamWidth = streamWidth,
+                streamHeight = streamHeight,
+                targetFrameRate = streamRealFrameRate,
+                refreshRateSwitch = true,
+                resolutionSwitch = false,
+            )
+        Assert.assertEquals(4, result?.modeId)
+    }
+
+    @Test
+    fun test4() {
+        val streamWidth = 1920
+        val streamHeight = 804
+        val streamRealFrameRate = 30f
+        val result =
+            RefreshRateService.findDisplayMode(
+                displayModes = ALL_MODES,
+                streamWidth = streamWidth,
+                streamHeight = streamHeight,
+                targetFrameRate = streamRealFrameRate,
+                refreshRateSwitch = false,
+                resolutionSwitch = true,
+            )
+        Assert.assertEquals(1, result?.modeId)
+    }
+
+    @Test
+    fun testFraction() {
+        val streamWidth = 1920
+        val streamHeight = 1080
+        val streamRealFrameRate = 30f
+
+        val displayModes =
+            listOf(
+                DisplayMode(0, 1920, 1080, 59.940f),
+                DisplayMode(1, 1920, 1080, 60f),
+//                DisplayMode(2, 1920, 1080, 29.970f),
+            )
+
+        val result =
+            RefreshRateService.findDisplayMode(
+                displayModes = displayModes,
+                streamWidth = streamWidth,
+                streamHeight = streamHeight,
+                targetFrameRate = 29.970f,
+                refreshRateSwitch = true,
+                resolutionSwitch = false,
+            )
+        Assert.assertEquals(0, result?.modeId)
+
+        val result2 =
+            RefreshRateService.findDisplayMode(
+                displayModes = displayModes,
+                streamWidth = streamWidth,
+                streamHeight = streamHeight,
+                targetFrameRate = 24f,
+                refreshRateSwitch = true,
+                resolutionSwitch = false,
+            )
+        Assert.assertEquals(1, result2?.modeId)
+    }
+}