Templated tests

[mefellows]

When generating pact tests, the output does not always match the existing style, idioms, frameworks and SDK versions as the current project the engineer is working on. For example, the test might generate chai matchers and assertions, for a project that uses Jest.

Additionally, the style of the test may not be consistent with the existing tests.

One way to address this problem, and improve the output, is to allow users to provide their own templates with their existing patterns and style encoded in them, when asking PactFlow to generate tests. PactFlow will use this as a template to inject the test cases into.

1. Ability to provide a (local) template when generating tests
2. Ability to specify an existing (cloud) template when generating tests
3. New permission will be created to allow users to specify local templates

In a future capability, we will support a template library within PactFLow:

1. Ability to upload templates to PactFlow into a template library (via API or UI)
2. Templates may be associated with the team or no team (follow the secrets model)
3. UI to manage the templates
4. Ability to restrict all of the above via RBAC
5. Permission to allow creating/updating/deleting (managing) and reading existing templates (at the * and team scope)