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

naming: prefer displayName over cn/sn

Closes #5

See merge request !4

Now we have on-boarded users, move away from being compatible with the
authenticator to using displayName in preference to cn/sn.

Closes #5

allow configuration of API batch size and inter-batch delay

Closes #2

See merge request !2

Clarify in documentation that there is a maximum API batch size of 1000.

remove useless progress indicator

Closes #4

See merge request !3

Closes #4

Add configuration parameters to tweak how we call the Google API. Allow
customisation of API batch size and the delay between calls to the API.
This allows us to work around some Google API rate limits.

Closes #2

initial implementation

Closes #1

See merge request !1

Provide an initial implementation f the tool and README documenting how
to install, configure and run it.

Closes #1