Some LESS parsers will get confused with the lack of file extension.
It's better to be explicit and in alignment with recent change in core
I379334d7729e587a2a00.
It was already weirdly mixed in this repo with some imports featuring
extension and some not.
Change-Id: If5065cf9e30289de9b4fd33315bd65b75959ecb7
Unifying variable naming to property-identifier-modifier scheme, while
also collecting all non-print values variables in corresponding file.
We will amend the `em` based values to calculations that will enable
rendered full pixel values and also fix some connected
usability issues in the future.
Change-Id: I378e8a2af91fe0790708e6fb2d2e7a5718ce93c5
