add yaml playout pre_roll instruction (#2228)

* add yaml playout pre_roll instruction

* add basic yaml validation

* validate all yaml playout content items

* fix yaml to json conversion

* update changelog

.editorconfig

@@ -7,6 +7,22 @@ insert_final_newline=false
 indent_style=space
 indent_size=4
 
+[*.json]
+ij_json_array_wrapping = normal
+ij_json_keep_blank_lines_in_code = 0
+ij_json_keep_indents_on_empty_lines = false
+ij_json_keep_line_breaks = true
+ij_json_keep_trailing_comma = false
+ij_json_object_wrapping = normal
+ij_json_property_alignment = do_not_align
+ij_json_space_after_colon = true
+ij_json_space_after_comma = true
+ij_json_space_before_colon = false
+ij_json_space_before_comma = false
+ij_json_spaces_within_braces = true
+ij_json_spaces_within_brackets = true
+ij_json_wrap_long_lines = false
+
 # Microsoft .NET properties
 csharp_new_line_before_members_in_object_initializers=false
 csharp_preferred_modifier_order=public, private, protected, internal, new, abstract, virtual, sealed, override, static, readonly, extern, unsafe, volatile, async:suggestion