Improve .editorconfig setup

Add rules for all the project files.
Inspired by android studio editorconfig, results in
all files containing newlines at the end of file for
consistent code style throughout the app.

Change-Id: Ifc98fcf75f8e78526a0e186b2b14d44f0f7e45ac

.editorconfig

@@ -1,4 +1,24 @@
+[*]
+charset = utf-8
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
 [*.{kt,kts}]
-indent_size=4
-insert_final_newline=true
-max_line_length=100
+indent_size = 4
+max_line_length = 100
+
+[app/src/main/res/values-*/strings.xml]
+insert_final_newline = unset
+trim_trailing_whitespace = unset
+
+[*.md]
+trim_trailing_whitespace = false
+
+[gradlew.bat]
+charset = latin1
+end_of_line = crlf
+insert_final_newline = false
+
+[.editorconfig]
+ij_editorconfig_spaces_around_assignment_operators = true