android: choosing theme and accent color (#967)

* Theme selector
- ability to select from three default choices: system theme, light, dark
- ability to choose color accent (primary color)

* Removed unused code and made small changes to colors and buttons

apps/android/app/src/main/res/values-ru/strings.xml

@@ -272,7 +272,7 @@
     <string name="chat_lock">Блокировка SimpleX</string>
     <string name="chat_console">Консоль</string>
     <string name="smp_servers">SMP серверы</string>
-    <string name="install_simplex_chat_for_terminal"><font color="#0088ff"><xliff:g id="appNameFull">SimpleX Chat</xliff:g> для терминала</font></string>
+    <string name="install_simplex_chat_for_terminal"><xliff:g id="appNameFull">SimpleX Chat</xliff:g> для терминала</string>
     <string name="use_simplex_chat_servers__question">Использовать серверы предосталенные <xliff:g id="appNameFull">SimpleX Chat</xliff:g>?</string>
     <string name="saved_SMP_servers_will_br_removed">Сохраненные SMP серверы будут удалены.</string>
     <string name="your_SMP_servers">Ваши SMP серверы</string>
@@ -468,6 +468,7 @@
     <string name="settings_experimental_features">Экспериментальные функции</string>
     <string name="settings_section_title_socks">SOCKS ПРОКСИ</string>
     <string name="settings_section_title_icon">ИКОНКА</string>
+    <string name="settings_section_title_themes">ТЕМЫ</string>
 
     <!-- DatabaseView.kt -->
     <string name="your_chat_database">Данные чата</string>
@@ -635,4 +636,15 @@
     <string name="update_network_settings_question">Обновить настройки сети?</string>
     <string name="updating_settings_will_reconnect_client_to_all_servers">Обновление настроек приведет к переподключению клиента ко всем серверам.</string>
     <string name="update_network_settings_confirmation">Обновить</string>
+
+    <!-- Default themes -->
+    <string name="theme_system">Системная</string>
+    <string name="theme_light">Светлая</string>
+    <string name="theme_dark">Темная</string>
+
+    <!-- Appearance.kt -->
+    <string name="theme">Тема</string>
+    <string name="save_color">Сохранить цвет</string>
+    <string name="reset_color">Сбросить цвета</string>
+    <string name="color_primary">Акцент</string>
 </resources>

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

@@ -277,7 +277,7 @@
   <string name="chat_lock">SimpleX Lock</string>
   <string name="chat_console">Chat console</string>
   <string name="smp_servers">SMP servers</string>
-  <string name="install_simplex_chat_for_terminal">Install <font color="#0088ff"><xliff:g id="appNameFull">SimpleX Chat</xliff:g> for terminal</font></string>
+  <string name="install_simplex_chat_for_terminal">Install <xliff:g id="appNameFull">SimpleX Chat</xliff:g> for terminal</string>
   <string name="use_simplex_chat_servers__question">Use <xliff:g id="appNameFull">SimpleX Chat</xliff:g> servers?</string>
   <string name="saved_SMP_servers_will_br_removed">Saved SMP servers will be removed.</string>
   <string name="your_SMP_servers">Your SMP servers</string>
@@ -470,6 +470,7 @@
   <string name="settings_experimental_features">Experimental features</string>
   <string name="settings_section_title_socks">SOCKS PROXY</string>
   <string name="settings_section_title_icon">APP ICON</string>
+  <string name="settings_section_title_themes">THEMES</string>
 
   <!-- DatabaseView.kt -->
   <string name="your_chat_database">Your chat database</string>
@@ -637,4 +638,15 @@
   <string name="update_network_settings_question">Update network settings?</string>
   <string name="updating_settings_will_reconnect_client_to_all_servers">Updating settings will re-connect the client to all servers.</string>
   <string name="update_network_settings_confirmation">Update</string>
+
+  <!-- Default themes -->
+  <string name="theme_system">System</string>
+  <string name="theme_light">Light</string>
+  <string name="theme_dark">Dark</string>
+
+  <!-- Appearance.kt -->
+  <string name="theme">Theme</string>
+  <string name="save_color">Save color</string>
+  <string name="reset_color">Reset colors</string>
+  <string name="color_primary">Accent</string>
 </resources>