move get device key API from client to crypto (#3899)

MatrixClient API was exposing two methods that only worked for legacy crypto:
- getDeviceEd25519Key
- getDeviceCurve25519Key

=> These are used in the react-sdk for some functionality (rageshake, sentry, rendez-vous).

I have deprecated those calls from MatrixClient and created a new API in CryptoApi (where it belongs):

getOwnDeviceKeys(): Promise<OwnDeviceKeys>

src/client.ts

@@ -2393,6 +2393,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
      *
      * @returns base64-encoded ed25519 key. Null if crypto is
      *    disabled.
+     *
+     * @deprecated Prefer {@link CryptoApi.getOwnDeviceKeys}
      */
     public getDeviceEd25519Key(): string | null {
         return this.crypto?.getDeviceEd25519Key() ?? null;
@@ -2403,6 +2405,8 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
      *
      * @returns base64-encoded curve25519 key. Null if crypto is
      *    disabled.
+     *
+     * @deprecated Use {@link CryptoApi.getOwnDeviceKeys}
      */
     public getDeviceCurve25519Key(): string | null {
         return this.crypto?.getDeviceCurve25519Key() ?? null;