[#1349] Basic Cookie Authentication (#1498)

* [#1349] Stub basic cookie authentication

* [#1349] Basic login page

Also adjusts WebView header color and shadow to match WebUI. WebUI uses
a background-image gradient to change the perceived color, which was not
noticed originally.

* [#1349] Handle login post

* [#1349] Redirect to previous URL

* [#1349] Return a basic 401 for api endpoints

Instead of redirecting to a visual login page, API should just indicate
the bad state

* Use more appropriate 303 redirect

* Update server/src/main/kotlin/suwayomi/tachidesk/server/JavalinSetup.kt

Co-authored-by: Mitchell Syer <Syer10@users.noreply.github.com>

* Update server/src/main/kotlin/suwayomi/tachidesk/server/JavalinSetup.kt

Co-authored-by: Mitchell Syer <Syer10@users.noreply.github.com>

* Lint

* Transition to AuthMode enum with migration path

* Make basicAuthEnabled auto property, Lint

* ConfigManager: Make sure to re-parse the config after migration

* basicAuth{Username,Password} -> auth{Username,Password}

* Lint

* Update server settings backup model

* Update comment

* Minor cleanup

* Improve backup legacy settings fix

* Lint

* Simplify config value migration

---------

Co-authored-by: Mitchell Syer <Syer10@users.noreply.github.com>

AndroidCompat/Config/src/main/java/xyz/nulldev/ts/config/ConfigManager.kt

@@ -138,7 +138,7 @@ open class ConfigManager {
      *  - adds missing settings
      *  - removes outdated settings
      */
-    fun updateUserConfig() {
+    fun updateUserConfig(migrate: ConfigDocument.(Config) -> ConfigDocument) {
         val serverConfig = ConfigFactory.parseResources("server-reference.conf")
         val userConfig = getUserConfig()
 
@@ -162,7 +162,11 @@ open class ConfigManager {
                 )
             }.forEach { newUserConfigDoc = newUserConfigDoc.withValue(it.key, it.value) }
 
+        newUserConfigDoc =
+            migrate(newUserConfigDoc, internalConfig)
+
         userConfigFile.writeText(newUserConfigDoc.render())
+        getUserConfig().entrySet().forEach { internalConfig = internalConfig.withValue(it.key, it.value) }
     }
 }