[docs] Migrate Testing pages

[sarjona]

The URL of the page on https://docs.moodle.org/dev/

https://docs.moodle.org/dev/Testing

Is this documentation specific to a Moodle version?

No

What location would you suggest in the new docs?

general/development/process/testing.md

Apart from that page, there are other pages related to Testing that might be migrated together:

• https://docs.moodle.org/dev/Testing_of_integrated_issues
• https://docs.moodle.org/dev/QA_testing
• https://docs.moodle.org/dev/Testing_instructions_guide
• https://docs.moodle.org/dev/Acceptance_testing