* add architecture styleguide
* be clearer about application architecture
* define as plugin architecture
and downplay the webpack alias and shims that are available
* fix typo, simplify server description
* Use uniquely and semantically named data attribute to select loading message, instead of CSS class since that creates a brittle coupling between JS and CSS.
* Formalize this rule in the CSS style guide.
The existing styleguide was in great need of a rewrite as it did not
reflect the conventions we're using in the codebase or even the best
practices that we follow. In some cases, the guidance it provided was
outright contrary to our current practices.
