fix(EMS-4100): country risk logic - quote - no online support

[ttbarnes]

Introduction ✏️

This PR fixes an issue where in the quote tool - if a country has no online support, it should redirect to a "Talk to EFM" exit page, instead of a "Get a quote by email" exit page.

Resolution ✔️

• Move appropriate TALK_TO_AN_EXPORT_FINANCE_MANAGER_EXIT constants and content strings into a shared file, since this is now used in both the quote tool and application eligibility.
• Update E2E country fixtures to include more "no online support" countries for the quote tool.
• Add/update E2E tests, add more "no online support" coverage.
• Update the quote tool's BUYER_COUNTRY POST controller to redirect to TALK_TO_AN_EXPORT_FINANCE_MANAGER_EXIT if no online support is available.
• Create new TALK_TO_AN_EXPORT_FINANCE_MANAGER_EXIT quote tool GET route and controller.
• Update requiredQuoteEligibilityDataProvided middleware to include TALK_TO_AN_EXPORT_FINANCE_MANAGER_EXIT.

Miscellaneous ➕

• Rename all instances of "Buyer body" to "Type of buyer". This URL was changed a long time ago - the "buyer body" instances caused some confusion.
• Rename NEED_TO_START_AGAIN E2E constant to NEED_TO_START_AGAIN_EXIT, to be consistent.
• Minor documentation improvements.