Added Japanese localization

[danesky-jp]

Japanese localization by me (danesky) is added as a part of contributions to SJ2021, hopefully. Fonts missing in vanilla Celeste are also provided.

At present, there are multiple png files, because information of all characters in Japanese.txt is embedded there. In the future, I may reduce the number of files by removing overlapping characters, but for now this is OK to me.

[WEGFan]

You can only enable the localization "mod" but without the fonts and launch the game, then you can type check_language japanese in the game console to get a list of missing characters, it will be written in japanese-missing-debug.txt in your game installation folder:

含項並節未類@抽証警複共布列依

The following is not needed after #370 gets merged.

Also you need to include the files to the project by adding `EmbeddedResource` to make it work properly in Everest.

Everest/Celeste.Mod.mm/Celeste.Mod.mm.csproj

Lines 182 to 185 in 106d7ed

	<EmbeddedResource Include="Content\Lua\typebuilder.lua">
	<LogicalName>Content\Lua\typebuilder.lua</LogicalName>
	</EmbeddedResource>
	</ItemGroup>

   <EmbeddedResource Include="Content\Lua\typebuilder.lua">
     <LogicalName>Content\Lua\typebuilder.lua</LogicalName>
   </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Japanese.txt">
+    <LogicalName>Content\Dialog\Japanese.txt</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese.fnt">
+    <LogicalName>Content\Dialog\Fonts\japanese.fnt</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese_everest_0.png">
+    <LogicalName>Content\Dialog\Fonts\japanese_everest_0.png</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese_everest_1.png">
+    <LogicalName>Content\Dialog\Fonts\japanese_everest_1.png</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese_everest_2.png">
+    <LogicalName>Content\Dialog\Fonts\japanese_everest_2.png</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese_everest_3.png">
+    <LogicalName>Content\Dialog\Fonts\japanese_everest_3.png</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese_everest_4.png">
+    <LogicalName>Content\Dialog\Fonts\japanese_everest_4.png</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese_everest_5.png">
+    <LogicalName>Content\Dialog\Fonts\japanese_everest_5.png</LogicalName>
+  </EmbeddedResource>
+  <EmbeddedResource Include="Content\Dialog\Fonts\japanese_everest_6.png">
+    <LogicalName>Content\Dialog\Fonts\japanese_everest_6.png</LogicalName>
+  </EmbeddedResource>
 </ItemGroup>

[danesky-jp]

Thank you for valuable information. Following the suggested procedure, I generated font files only for missing characters.