Removed .subscribeOn(Schedulers.boundedElastic()) from vault token suppliers

Author: artem-v

vault/src/main/java/io/scalecube/security/vault/VaultClientTokenSupplier.java

@@ -12,7 +12,6 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import reactor.core.publisher.Mono;
-import reactor.core.scheduler.Schedulers;
 
 public final class VaultClientTokenSupplier {
 
@@ -88,7 +87,6 @@ public VaultClientTokenSupplier vaultRole(String vaultRole) {
   public Mono<String> getToken() {
     return Mono.fromRunnable(this::validate)
         .then(Mono.fromCallable(this::getToken0))
-        .subscribeOn(Schedulers.boundedElastic())
         .doOnSubscribe(s -> LOGGER.debug("[getToken] Getting vault client token"))
         .doOnSuccess(s -> LOGGER.debug("[getToken][success] result: {}", mask(s)))
         .doOnError(th -> LOGGER.error("[getToken][error] cause: {}", th.toString()));

vault/src/main/java/io/scalecube/security/vault/VaultServiceTokenSupplier.java

@@ -14,7 +14,6 @@
 import org.slf4j.LoggerFactory;
 import reactor.core.Exceptions;
 import reactor.core.publisher.Mono;
-import reactor.core.scheduler.Schedulers;
 
 public final class VaultServiceTokenSupplier {
 
@@ -112,7 +111,6 @@ public Mono<String> getToken(Map<String, String> tags) {
             vaultToken -> {
               final String uri = buildServiceTokenUri(tags);
               return Mono.fromCallable(() -> rpcGetToken(uri, vaultToken))
-                  .subscribeOn(Schedulers.boundedElastic())
                   .doOnSubscribe(
                       s ->
                           LOGGER.debug(