Remove some minor settings

Some spring cleaning to remove some unnecessary complexity so things are easier to maintain.

- Start screen: redundant with app shortcuts in Android 7.1+
- Jump to chapters: irrelevant in tablet mode and people can scroll a tiny bit if they really have to
- Option to not scroll away bottom nav: issues with fast scroll will be irrelevant with it being replaced or removed in the Compose migrations

Get ready for people malding over their special needs. https://xkcd.com/1172/

app/src/main/res/layout/main_activity.xml

@@ -86,6 +86,7 @@
         android:layout_height="wrap_content"
         android:layout_gravity="bottom"
         android:clickable="true"
+        app:layout_behavior="eu.kanade.tachiyomi.widget.HideBottomNavigationOnScrollBehavior"
         app:layout_insetEdge="bottom"
         app:menu="@menu/main_nav"
         tools:ignore="KeyboardInaccessibleWidget" />

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

@@ -170,14 +170,12 @@
     <string name="alignment_top">Top</string>
     <string name="alignment_center">Center</string>
     <string name="alignment_bottom">Bottom</string>
-    <string name="pref_hide_bottom_bar_on_scroll">Hide bottom bar on scroll</string>
     <string name="pref_category_timestamps">Timestamps</string>
     <string name="pref_relative_format">Relative timestamps</string>
     <string name="pref_relative_time_short">Short (Today, Yesterday)</string>
     <string name="pref_relative_time_long">Long (Short+, n days ago)</string>
     <string name="pref_date_format">Date format</string>
 
-    <string name="pref_start_screen">Start screen</string>
     <string name="pref_confirm_exit">Confirm exit</string>
     <string name="pref_manage_notifications">Manage notifications</string>
 
@@ -210,7 +208,6 @@
     <string name="pref_library_columns">Items per row</string>
     <string name="portrait">Portrait</string>
     <string name="landscape">Landscape</string>
-    <string name="pref_jump_to_chapters">Jump to chapters on open</string>
 
     <string name="pref_category_library_update">Global update</string>
     <string name="pref_library_update_interval">Automatic updates</string>