New CSP self-checks in U1-U3; Revisions to Sparks U3 (adding basic:bit board instructions, improving troubleshooting in TG, updating MicroBlocks images); other minor revisions to both curricula

Revisions to Spanish version of 5.3.1: Analyzing Global Health Data and Spanish version of 5.3.3: Importing and Accessing Data, revisions to Unit 1 images, minor revisions to vocabulary boxes throughout course.

Revisions to 5.3.3: Importing and Accessing Data and Spanish version of 5.3.3: Importing and Accessing Data and other minor revisions and improvements.

Revisions to English version of 5.3.1: Analyzing Global Health Data (Spanish revisions coming soon), additional self-check questions in Unit 1 (Spanish), and updates to student recruitment resources.

Accessibility improvements, reorganizing Teacher Resources page, and other minor revisions and improvements.

• Accessibility Enhancements
• Minor sparks fixes / updates
• CSP fixes
• Link to sparks on the homepage

Swaps page 1.1.1 and 1.1.2, revises 1.1.2, and adds Teacher Guide page about student accounts and privacy.