update kirby to v5 and add refresh cache panel view button

public/site/plugins/refresh-cache-button/.editorconfig

@@ -0,0 +1,20 @@
+# This file is for unifying the coding style for different editors and IDEs
+# editorconfig.org
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+end_of_line = lf
+insert_final_newline = true
+trim_trailing_whitespace = true
+
+[*.php]
+indent_size = 4
+
+[*.md,*.txt]
+trim_trailing_whitespace = false
+insert_final_newline = false
+
+[composer.json]
+indent_size = 4