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

Snowplow only accepts decimals for value
This MR removes sending of value implicitly with the value attribute

Removing extra blank lines in docs that serve
no purpose, as well as some --- lines that also
are not needed.

All code blocks should be surrounded by blank lines

Updating redirected links in the development, install, policy
raketasks and university dirs. Should now link to final
URL to avoid redirect hops

Also fixes instances in Markdown that broke the rule.

Fixing square brackets, links, etc in:
  merge_requests.md
  vulnerabilities.md
  issues.md
  issues_statistics.md
  pipelines.md
  services.md
  group_milestones.md
  milestones.md
  runners.md
  changelog.md
  issue_workflow.md
  elasticsearch.md
  api_graphql_styleguide.md
  automatic_ce_ee_merge.md
  file_storage.md
  architecture.md
  database_debugging.md
  index.md
  index.md
  frontend_testing.md
  pry_debugging.md
  vue.md
  development_process.md

Linting rule not enabled for now
because tooling produces false
positives.

Add links to useful browser extensions and learning resources to the
FE-accessibility documentation.