This commit prepares the frontend code to be consumed by webpack.
It is a hack: In theory, modules should be declaring and importing the
modules they depend on and the globals they expose directly.
However, that requires significant per-module work, which we don't
really want to block moving our toolchain to webpack on.
So we expose the modules by setting window.varName = varName; as
needed in the js files.
Adds search_pill.js to the static asset pipeline. The items
for search pill contain 2 keys, display_value and search_string.
Adding all the operator information i.e the operator, operand and
negated fields along with the search_string and description was tried out.
It was dropped because it didn't provide any advantage as one had to
always calculate the search_string and the description from the operator.
Armaan Ahluwalia
Shubham Padia