Add Ramp vendors once, with the agreement on file

**Objective:** Add `{vendor-name}` (country `{country}`, contact `{contact-email}`) to Ramp as a vendor and, if an end date `{agreement-end-date}` is given, record an agreement.

**Step 1: Duplicate check**

Call `ramp-get-vendor` with `name.contains` set to the vendor name, and again with `legal-name.contains`. If anything similar exists, show it and stop unless the user says it is a different vendor.

**Step 2: Confirm**

Show the details to be created. An agreement also needs a start date, total value, auto-renewal and notification choices. Ask for any of these that are missing. Ask the user to confirm.

**Step 3: Create**

Call `ramp-vendor-add`. Re-read with `ramp-get-vendor` to get the new id. Only if an agreement was requested and confirmed, call `ramp-vendor-agreement-add` with that vendor id.

**Step 4: Report**

The vendor id, the agreement id if any, and anything left to do (bank account, contact details).

**Rules & Guidelines:**

* Allowed writes: `ramp-vendor-add` and `ramp-vendor-agreement-add`, once each, after confirmation.
* Never call `ramp-vendor-delete` or `ramp-vendor-update-bank-accounts`. Bank details are entered by the user in Ramp.

**Validation:**

* If the contact email looks invalid, stop and ask.