Add missing FK indexes

[tmfrnz]

Join tables missing both FK indexes:

• measure_categories: no index on measure_id or category_id
• measure_indicators: no index on measure_id or indicator_id
• recommendation_categories: no index on recommendation_id or category_id
• recommendation_recommendations: no index on recommendation_id or other_recommendation_id
• user_categories: no index on user_id or category_id

Join table missing one FK index:

• recommendation_measures: has recommendation_id and measure_id but not a composite

Other tables missing FK indexes:

• framework_frameworks: no index on framework_id or other_framework_id
• categories.parent_id: no index
• taxonomies.parent_id: no index