Make bulk import page instructions a bit clearer

[Robert Lyon]

The bulk import page instructions are not quite clear in a couple of places
- the structure if the zip file to import
- the path to fetch the file from

[Mahara Bot (dev-mahara)]

Patch for "master" branch: https://reviews.mahara.org/10258

[Steven (stevens-q)]

Commit hash: a2ed4665f3e66ff2558fb3afec59e7442f63051b
Environment tested: Master
Browser tested: Chrome
Theme used: Raw

PRECONDITIONS:
------------------------
1) Site admin exists

TEST STEPS:
------------------------
1) Log in as Site admin
2) Browse to /admin/users/bulkimport.php
3) Verify that the page has the following sections
    a) usernames.csv will look something like this:: ✔
    b) The structure of your ZIP file, eg import.zip file will be: ✔

NOTE; see the attached screenshot

Catalyst QA Approved ✔

[Mahara Bot (dev-mahara)]

Reviewed: https://reviews.mahara.org/10258
Committed: https://git.mahara.org/mahara/mahara/commit/a2ed4665f3e66ff2558fb3afec59e7442f63051b
Submitter: Cecilia Vela Gurovic (<email address hidden>)
Branch: master

commit a2ed4665f3e66ff2558fb3afec59e7442f63051b
Author: Robert Lyon <email address hidden>
Date: Mon Aug 12 09:16:47 2019 +1200

Bug 1839785: Updating the bulkimport instructions

behatnotneeded

Change-Id: I8334ea625a2f2790bed846913990cecd68b24a70
Signed-off-by: Robert Lyon <email address hidden>