KG - More OS Settings Configurations Updates

[kayla-glick]

Changes:

1. Added any missing constants to defaults.json and updated as much data as I could.
2. Changed the temporary rake task to use defaults.json instead of application.yml.
3. Fix several constant calls still remaining within the application.
4. Removed several unused consants.
5. Removed application.yml constants initializers.

STILL TODO:

• Add trys to all value calls to prevent crashes? May also not want to do this so that we will receive the error and know that the setting is not defined.
• Move data change from task to the migration
• Update application documentation to reflect new configuration
• Move other configurations to database? - epic.yml, ldap.yml, travis.yml, database.yml

Note: Please review the defaults.json changes. Focus on language of friendly name and description, and the parent associations. Please make comments with recommended changes.

Note 2: Specs are expected to fail right now. The base branch os-move-configuration-to-database is failing. This is something we need to look into.