Export profile base interface alongside the profile class

[aartaka]

I was testing CCDA generation and writing tests for it. And I noticed that CCDA profile classes are exported, while interfaces behind them aren’t. Test snippet (added as an extra file in examples/typescript-ccda/):

import type * as CCDA from "./fhir-types/hl7-cda-us-ccda";
import type * as FHIR from "./fhir-types/hl7-fhir-r4-core";

function medicationStatementToMedicationActivity (stat: FHIR.MedicationStatement): CCDA.MedicationActivity | null {
    return null;
}

it fails with CCDA.MedicationActivity not being found.

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With this PR, package index.ts has all the necessary type exports, like

export type { MedicationActivity } from "./profiles/MedicationActivity";

[ryukzak]

LGTM except comment. Also, please, fix CI.