Ensure we can still build installers for IGB 9 versions

We decided to punt on trying to build pre-9.1.8 versions because the bitbucket pipeline configuration is too out-of-date. If we need to update it, we can do that, but right now it isn't necessary.

Update:

• After defining the above-mentioned repository variables, I could build release-9.1.8
• I looked at the file https://bitbucket.org/lorainelab/iipc/src/master/bbpipelines_environment_variables.txt and noted it contains records of when and how new key signing passwords were defined
• This file also contains the license key for version 7 Install4J. We probably need to use this to build older version of IGB, using older docker images that are defined in the bitbucket pipelines yml file

Added Install4J version 8 password to "env.sh" file:

https://bitbucket.org/lorainelab/iipc/src/master/env.sh

Note that to build IGB 9.1.8, you have to provide bitbucket pipeline with environment variables listed in the above file, including:

• windows key password
• mac os key password
• install4j version 8 password