Implement MongoDB indexing and performance optimization

[anitnilay20]

Description

Add index management and performance optimization features for MongoDB.

Requirements

• Index creation and management
• Compound index support
• Text search indexes
• Geospatial indexes
• Index performance analysis
• Query optimization hints
• Write comprehensive tests

Acceptance Criteria

• Complete index management
• Performance monitoring tools
• Query optimization features
• Index recommendation system

Files to create

• beatrix_core/src/mongo/indexes.rs
• beatrix_core/src/mongo/performance.rs

Example Usage

User::create_index()
    .field(User::email(), IndexType::Ascending)
    .field(User::status(), IndexType::Ascending)
    .unique(true)
    .execute(&db).await?;

let results = User::find()
    .filter(doc! { "": { "": "john" } })
    .hint("text_index")
    .execute(&db).await?;