Fixed Mixed Evaluation - Duplicate Self-Evaluations

[josephkh]

1. Copied the Self-Evaluation field from event-settings to mixeval-settings. Note: The copied Self-Evaluation field will be visible Only in 'edit' mode if the mixed evaluation is attached to an event.
2. Renamed the Self-Evaluation label on the mixeval-template-page and form title to read "Include Additional Questions for Reflection".
3. Changed the behaviour of event settings for mixed evaluations to always display "Additional Questions for Reflection" questions that are part of the evaluation template regardless of event settings.