Refactor sync (and config)

Closes #11

See merge request !19

Resolve "Make use of the new givenName attribute from Lookup"

Closes #14

See merge request !18

Add logging of Google API batch request progress

Closes #26

See merge request !16

Support authenticating with the LDAP server over SSL

Closes #27

See merge request !17

To facilitate running the sync tool outside of the CUDN (such as when testing
remotely), this commit adds configuration options for specifying credentials
for authenticating with the LDAP server over SSL. SSL will automatically be
used when these credentials are supplied.

Add `tox.sh` script for running tox tests locally.

We often need to call the Google API with large numbers of requests
(thousands), so the API is called with batches of requests. Quota limits are
often hit, so logging when an individual batch has completed gives confidence
that progress is being made. This commit adds this logging.

Retry all > 400 errors on a list operation failing

Closes #25

See merge request !15

Add --group-settings option

Closes #22

See merge request !13

Clean Group Descriptions

Closes sync-deploy#11

See merge request !14

Admin user optional

See merge request !12

Synchronise Lookup institutions.

Closes #7

See merge request !10

This causes Lookup institutions and their members to be synchronised
with groups in Google, in a similar way to Lookup groups. The unique
identifier of the group in Google is it's email address:

email = {instID.lower()}@{insts_domain}

where {insts_domain} is a configurable secondary domain (noting that
the local part of the email address is required to be lowercase,
whereas all instIDs from Lookup are uppercase).

Move includeInGlobalAddressList defaults to True.

See merge request !11

Setting includeInGlobalAddressList to false will make these groups not searchable in the sharing UI

gapiutil: retry after all errors

Closes #13

See merge request !9

Rather than simply retrying after 503 errors, retry after all error
responses since we have also been seeing some spurious 400 responses
from Google.

Limit group descriptions to 300 characters.

Closes #12

See merge request !8

Synchronise Lookup groups.

Closes #10

See merge request !7

This causes Lookup groups and their members to be synchronised with
groups in Google. As for people, there are various configuration
options to control which groups to synchronise, what settings should
be applied to them, and to enforce limits on the number of changes the
script will perform.

The group email and display name in Google are based on the Lookup
groupID and groupName, noting that the email is the group's unique
identifier in Google:

email = {groupID}@{groups_domain}
name = {groupName}{group_name_suffix}

where groups_domain is a configurable secondary domain for groups in
Google, and group_name_suffix is a configurable suffix appended to
group names in Google.

Set organization unit path when creating new users

Closes #8

See merge request !6

Retry API requests when a HTTP 503 "Service unavaliable" is received

Closes #6

See merge request !5