Clarify configuration process in documentation

[juggernot325]

Description

This PR adds some additional verbiage to the examples/README.md file on how to configure BloodHound using the bloodhound.config.json file. Issue #207 highlighted that this is not clear in the previous version of the README as it was only documented in the docker-compose.yml file.

Motivation and Context

• Avoid confusion when configuring BloodHound

How Has This Been Tested?

• Verified the steps documented correctly apply the desired changes

Types of changes

• Chore (a change that does not modify the application functionality)
• Bug fix (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 change)

Checklist:

• Documentation updates are needed, and have been made accordingly.
• I have added and/or updated tests to cover my changes.
• All new and existing tests passed.
• My changes include a database migration.