Adding env var to ES to stop bootstrap checks

[benosteen]

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Description of Change

It causes Elasticsearch to run in a developmental mode, causing some preflight checks to become logged warnings, rather than critical errors. This is to avoid the Elasticsearch service from closing pre-emptively on Docker Hub, as the test host DH uses may have the vm.max_map_count set too low, or a related soft error for a test instance.

Issues Solved

#4800

Checklist

• Unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

[mradamcox]

Seems that this is related to #2746