[Connector Builder] Handle interpolated options values during YAML -> UI conversion

[lmossman]

Context

Some fields interpolate options values into their values, e.g. here:

  requester:
    type: HttpRequester
    name: "{{ options['name'] }}"

These interpolated values need to be handled somehow in the UI, since users can't specify $options blocks in the UI view.

Acceptance Criteria

• {{ options['var'] }} interpolated strings are resolved in the /manifest/resolve endpoint in the connector builder server
• More complicated interpolations involving options, and other non-options interpolations, are not resolved by the endpoint