Update the "Getting Started" doc

See merge request elixxir/xxdk-dev-docs!5

See Jira story for details: https://privategrity.atlassian.net/browse/XX-3800

Include example output in the "Testing With CLI-Generated Contact Files" section of the "Getting Started" doc

Docusaurus site

See merge request elixxir/xxdk-dev-docs!4

Update footer, favicon

See merge request elixxir/xxdk-dev-docs!3

Bring master up to date, merge updated CI

See merge request elixxir/xxdk-dev-docs!2

# Conflicts:
#   .gitlab-ci.yml
#   docusaurus-site/docusaurus.config.js

Push existing docs with CI

See merge request elixxir/xxdk-dev-docs!1