Load config yaml as ast to be able to report errors position

[timotheeguerin]

Currently when loading the config we are not able to report where in the config file is the invalid property/value.

We can switch from js-yaml to yaml which provides an AST presentation and would allow us to give a better error reporting.

This would also set the groud for an emitter to report a diagnostic on its emitter options and we'd be able to track back where that option is defined.

[markcowl]

Describe the breaking change
Change the yaml library dependency from js-yaml to 'Yaml'. The public API for loading config is not changed, but there may be slightly different behavior for those loading config giles separately.

Back-compat design to avoid immediate breaking
None, as emitters and libraries receive resolved config for their options, and do not / should not independently load config files.

Link to detailed breaking design
This issue

Impact
This change affecting:

• ARM
• Data-plane
• Existing specs: approx. # of service/spec impacted
• New specs
• Emitters
• SDK

Targeted Sprint
Sprint: September 2023

Additional information
Add any other information about the change including fixes for here.