Auto merge of #14316 - canaltinova:stylo-properties, r=emilio

Implement parsing/serialization and/or gecko glue for some properties

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The PR covers implementation and/or gecko glue for these properties:

1. Implemented parsing/serialization and gecko glue for column-rule-width, column-rule-color and column-span longhand properties (column-span is not implemented in gecko yet but I wanted to complete column properties :) )
2.  Implemented parsing/serialization and gecko glue for text-emphasis-color longhand and text-emphasis shorthand properties.
3. Implemented gecko glue for column-gap and order properties

I implemented column-rule-width and column-rule-color properties with `-moz-` prefixes, but I can remove them if it's not right.
I coudn't test them in full stylo build yet (LLVM messed up my current clang). But I'll test them soon.

r? @Manishearth or @emilio

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