CLI tool is not replacing '$' placeholders with environment variables

**Describe the bug**
CLI tool is not replacing '$' placeholders (indented more than one level) with environment variables.

**To Reproduce**
Example manifest file:
```yml
packages:
__APP_PACKAGE__:
version: 1.0.0
license: Adobe-2006
actions:
someAction:
function: dist/someAction
runtime: nodejs:10
web-export: true
annotations:
final: true
inputs:
eventingConnection:
bootstrapServers: $BOOTSTRAP_SERVERS
saslUsername: $SASL_USERNAME
```

**Expected behavior**
I expect aio cli tool to replace $ placeholders with environment variables regardless of the indentation level.

**Additional context**
An example error:
```
Error: Error connecting to the host: $BOOTSTRAP_SERVERS failed - getaddrinfo ENOTFOUND
```

使用提供的 manifest 和包含 $BOOTSTRAP_SERVERS 及 $SASL_USERNAME 的嵌套输入复现该问题。首先跟踪 CLI 的 manifest 环境变量替换路径；当无论缩进如何都能替换占位符，并且提供的连接错误不再包含字面占位符时，即表示完成。

由索引模型根据 Issue 内容生成。