Refactor deprecated ECX resources to Fabric in examples

[displague]

ECX Resources referenced in documentation and example must be updated to reflect Fabric Resources.
This is needed because of the deprecation of ECX APIs: https://developer.equinix.com/dev-docs/fabric/api-reference/layer-2-buyer-apis-v3

• Markdown references
• HCL references
• Terraform modules in the GH Equinix and Equinix-Labs orgs also reference ECX. Issues will be created in those modules referring to this issue. These will be visible below.

Originally posted by @thogarty in #445 (comment)