[bitnami/moodle] modify readme by non-containerized dbs

[crvargasm]

Detail

This PR adds a new section to the documentation titled "Connecting to a Non-Containerized Database", which provides detailed guidance on:

• The required MySQL user permissions for Moodle to function properly.
• A technical explanation of potential compatibility issues when using external or cloud-managed MySQL-compatible databases (e.g., Amazon Aurora).
• Specific problems related to the ROW_FORMAT=DYNAMIC directive included in the default docker-compose.yml used by the Bitnami Moodle container.

🧩 Problem Addressed

The current Bitnami documentation does not mention:

• The exact privileges the Moodle MySQL user must have.
• Compatibility concerns when using external databases that are not fully MySQL-compliant.

This omission can result in hard-to-debug issues like schema creation failures, permission errors, or "Row size too large" errors during initial setup or upgrades.

✅ Proposed Solution

• Add a Markdown section with SQL examples for creating the Moodle database and user with proper permissions.
• Add warnings about unsupported or partially supported database engines (e.g., Amazon Aurora).
• Include a technical explanation of how ROW_FORMAT=DYNAMIC interacts with different database engines and why this can lead to installation or runtime issues.

📎 References

• Moodle official database setup guide
• MySQL InnoDB row format documentation

🛠️ Notes

• This does not change any application logic or container configuration.
• It is intended solely to improve the developer/operator onboarding experience when using non-containerized databases with Bitnami's Moodle image.