Resolve Markdown ordered lists not conforming to styleguide

What does this MR do?

The GitLab documentation style guide requires that ordered lists items are always prefixed with 1..

This avoids needing to renumber the entire list when inserting new steps and simplifies ordered list creation.

This MR:

• Fixes most (if not all) instances of ordered lists not adhering to the style guide.
• Other markdown or grammar issues if they are located near a list fix.
• Converts some ordered lists to unordered lists if appropriate.

Related issues

Relates to: https://gitlab.com/gitlab-com/gitlab-docs/issues/287

Author's checklist

• Apply the correct labels and milestone
• Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails

Review checklist

• Your team's review (required)
• PM's review (recommended, but not a blocker)
• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards