Use promises to order the updates of variable options so that
parents are always updated before children.
This ensures that we only need to query the datasource once per
variable as variables that depend on other variables will only be
processed once their parent has been.
This commit also ensures that variable options are refreshed if
"refresh_on_load" is true even when query params are used to
set the variable seltion.

closes #4250

this is a quick hack to support repo url as parameter. Will refactor
later

Fixing language plus typos

Hiding password text

closes #4249