* eph: add ephemeral resource
Adds a new example ephemeral resource using a required configurable attribute and an example ID.
* tools: bump terraform-plugin-docs
Bump to the latest stable release, as it includes support for ephemeral resource documentation generation.
* docs: add ephemeral resource documentation
* provider: register new example ephemeral resource
* eph: improve alphabetical ordering of struct fields
* eph: use a computed 'value' attribute
To help provider developers easily understand the concept of ephemeral resources, we use a 'value' attribute in the schema, which is set to an example token (token-123).
* docs: update ephemeral resource docs
* provider: create a separate echo provider factory container
Since not every acceptance test requires an ephemeral provider server for the CLI to connect to and interact with, this introduces a separate provider factory container that includes the echo provider.
* eph: add basic acceptance test for ephemeral resource
* docs: rename ephemeral resource configuration file
* eph: improve http response diag
