Add support for Mermaid.js diagram tool in blogs and docs

[willihay]

Signed-off-by: Willow Hayward 17654918+willihay@users.noreply.github.com

Change summary

• Added support for Mermaid.js diagram tool in blogs and docs content.
• Mermaid version and SRI integrity check defined in site config.

Here's a screenshot of the smoketest (since smoke test is no longer built in deploy preview):

Submission Checklist:

• Descriptive active voice - Do descriptive sentences have a clear subject and action verb?
• Answer the question at hand - Does the documentation answer a what, why, how, or where type of question?
• Consistency - Does the content consistently follow the Style Guide?
• Help the user - Does the documentation show the user something meaningful?

[cgalvan]

Cool!