Create doc for `high_entropy_blobs` rule

[maxrake]

Overview

We need a standard markdown "learn more" doc for the "High entropy blobs" rule.

Additional context

It should follow the same format and style as the rest of the analytics docs. The doc should be called "high_entropy_blobs.md" to match the existing published link from the rule.

Acceptance Criteria

• [x] The "Learn More" page is hosted at https://docs.phylum.io/analytics/high_entropy_blobs
• [x] The "Issue Tags" page is updated with an entry and link to the new page