feat: support array as arg for CatalogBuilder.addEntityProvider and others

Allows to use e.g.

```
builder.addEntityProvider(getArrayOfProviders());
```

instead of

```
builder.addEntityProvider(...getArrayOfProviders());
```

Signed-off-by: Patrick Jungermann <Patrick.Jungermann@gmail.com>

docs/integrations/aws-s3/discovery.md

@@ -67,7 +67,7 @@ import { AwsS3EntityProvider } from '@backstage/plugin-catalog-backend-module-aw
 const builder = await CatalogBuilder.create(env);
 /** ... other processors and/or providers ... */
 builder.addEntityProvider(
-  ...AwsS3EntityProvider.fromConfig(env.config, {
+  AwsS3EntityProvider.fromConfig(env.config, {
     logger: env.logger,
     schedule: env.scheduler.createScheduledTaskRunner({
       frequency: { minutes: 30 },

docs/integrations/gerrit/discovery.md

@@ -30,7 +30,7 @@ import { Duration } from 'luxon';
 const builder = await CatalogBuilder.create(env);
 /** ... other processors and/or providers ... */
 builder.addEntityProvider(
-  ...GerritEntityProvider.fromConfig(env.config, {
+  GerritEntityProvider.fromConfig(env.config, {
     logger: env.logger,
     schedule: env.scheduler.createScheduledTaskRunner({
       frequency: { minutes: 30 },