Move streaming frontend bundle to separate action

What does this MR do and why?

Contributes to #391841 (closed)

Problem

Streaming code is automatically loaded for blame page even if it's not needed.

Solution

Only load streaming related javascript for blame streaming action.

• Add new route: /-/blame/master/CHANGELOG.md/streaming for streaming code
• Update links to streaming page
• Load streaming code only for new route

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.