set sec-username/sec-roles in webpack proxy config

[landryb]

allows testing features restricted to connected users

/cas correctly proxies to cas, but /whoami still replies {"GeorchestraUser":null} so the header shows the login button.

@f-necas : using:

-const DEV_HOST = "localhost:8080";
+const DEV_HOST = "georchestra.example.org:8180";

the page header still doesnt show me the logged in button, while mapstore itself shows me the plugins restricted to an admin user (eg save/delete/etc etc) so the authenticated requests to /rest work with sec-username/sec-roles only.

what were the headers necessary for /whoami to correctly find the user ? against a throwaway instance i can't figure that out...

curl -H sec-username:testadmin -H sec-proxy:true -H sec-roles:ROLE_MAPSTORE_ADMIN -H sec-org:C2C \
       -H 'sec-orgname: Test Org' http://georchestra.example.org:8180/whoami
{"GeorchestraUser":null}

[landryb]

@Gaetanbrl @pierrejego you might be interested in that too, to test authenticated-only features :)