Following the single docs codebase change, all internal links
should be relative. Also cleans up one table

Resolve "Export frontend fixtures as pipeline artifact"

Closes #64722 and #59166

See merge request gitlab-org/gitlab-ce!30917

Moves every fixture source file from
spec/javascripts to spec/frontend

Introduces frontend:fixtures rake task to replace
karma:fixtures and update documentation and CI scripts
to match

Ensure that all numbered lists use only 1. and no other numbers.
Also ensure that numbered lists use proper spacing.

The documentation referred to the .act method
This MR changes this to refer to the preferred
.perform method

Correct the spacing of unordered markdown lists
in docs, to maintain standards of documentation.

Documentation was lacking for the [data-qa-selector]
method of defining methods vs .qa-selector method.

A "bad" example was given, however no solution was provided
for fixing the bad example