Make import.sh more robust supporting more environments

[kjpopov]

With this change proposal I am making import.sh more flexible to support more environments and arangosh parameters to be configurable not hardcoded to -s.

Running the current master version results to an error message probably because of an obsoleted option -s

$ arangosh -s
Error while processing command-line options for arangosh:
  unknown option '--s'

This proposed solution is tested and works well for me with arangodb v3.4.7 osx Mojave 10.14.5
and arangodb installed via brew install arangodb

[OmarAyo]

Hi @kjpopov

Many thanks for contributing. We are obliged by law to have a signed scanned copy of a Contributor License Agreement (CLA) to be able to accept pull requests to the official ArangoDB repository

We use an Apache 2 CLA for ArangoDB and its companion projects, which can be found here: https://www.arangodb.com/documents/cla.pdf
Just fill in the form, sign and send a scanned copy over to cla@arangodb.com

Thank you