Add Hypothesis annotation/highlighting to blog

[0xdevalias]

Appears to have similar features to how Medium's highlighting works. Would probably also be worthwhile assessing what other projects/services exist that do similar, and compare/contrast them first.

• https://web.hypothes.is/
• https://web.hypothes.is/developers/
• https://h.readthedocs.io/
  • https://h.readthedocs.io/projects/client/en/latest/publishers/embedding/
  • https://h.readthedocs.io/en/latest/api/
    • https://h.readthedocs.io/en/latest/api-reference/v1/
    • https://hypothes.is/api/
• https://github.com/hypothesis
• https://github.com/hypothesis/h