Use constant for yoast-seo/editor

[vraja-pro]

What is the goal of this issue?

Cleanup the use of hard coded "yoast-seo/editor"

What needs to be done to achieve the goal?

• Create a constant file
• Add a constant for Store name ("yoast-seo/editor")
• Import to all files it is used and replace with the hard coded value.

Does the issue still need UX or research?

If available: what are the tips for fixing the problem or possible solutions?

What is the expected result/behavior?

Should documentation be added or updated for this change? and if so, where?