webpack: Remove LoaderOptionsPlugin.
webpack: Remove LoaderOptionsPlugin.

This seemed to exist for compatibility with webpack 1.

Signed-off-by: Anders Kaseorg <dfdb7392591db597bc41cf266a9c3bc12a2706e5@zulip.com>

zulip/zulip,kou/zulip,rht/zulip,rht/zulip,andersk/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,zulip/zulip,zulip/zulip,eeshangarg/zulip,kou/zulip,andersk/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,zulip/zulip,andersk/zulip,eeshangarg/zulip,rht/zulip,eeshangarg/zulip,andersk/zulip,andersk/zulip,rht/zulip,andersk/zulip,kou/zulip,rht/zulip,eeshangarg/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,zulip/zulip,kou/zulip