Add SUMO rules mentions & Improve AAQ step 3

[denyshon]

Rebased #7114.

Changes

• Add SUMO rules mentions when creating/editing a question, an answer, a forum thread, a forum post, a KB forum thread or a KB forum post (#2196).
• In AAQ step 3, replace "Subject:" with "Summarize your question" and add help text for this field.
• In AAQ step 3, display the Troubleshooting Info help text above the Share Data button, right after the field name.
• In AAQ step 3, add the "tb_version" extra field (#2536).
• In AAQ step 3, autofill the OS version field for Thunderbird.
• Fix the issue with the Share Data button not working when editing a question (#1642).
• Do not display the Common responses button when editing a question.
• Improve accessibility.
• Use "Windows 10/11" when there is not enough info to identify the exact Windows NT 10.0 version (#2700).
• Add l10n comments.
• Improve i18n, internationalize some alt strings
• Move repeated Helpful Tip code to a macro
• Remove an unused variable from forms.py

Resolves #2196, #2536, #1642, #2700.

Screenshots

AAQ step 3 (Firefox): [click to expand]

AAQ step 3 (Firefox) after clicking the Share Data button, in case we failed to pull the data: [click to expand]

AAQ step 3 (Thunderbird): [click to expand]

An example of how the editor looks on the updated surfaces (except for questions): [click to expand]

Note: Some icons in the screenshots may be missing because they were taken on a test setup.

TODO [admin]

Once this PR is merged, the following changes have to be made via the admin console:

• "tb_version" needs to be added to the Thunderbird & Thunderbird for Android AAQ Configurations' extra fields (for the "Thunderbird version" field to be displayed).
• (optional, but recommended) The "Windows 10/11" tag needs to be created (for it to be applied when we can't determine whether a user is on Windows 10 or Windows 11).