Add --recursive option for config Import

[Maksold]

Issue

.

Proposed changes

I want to support this config files structure

magento_root
...
├── config
│   └── store
│       ├── base
│       │       ├── vendor1
│       │       │   ├── geoip.yaml
│       │       │   └── storepickup.yaml
│       │       └── vendor2
│       │           └── general.yaml
│       └── staging
│               ├── vendor1
│               │   └── recaptcha.yaml
│               └── vendor2
│                   └── general.yaml
...

For this purpose I added -r option for Import command. It allows to find config files recursively and import them.

So I use this command bin/magento config:data:import config staging -r to import my configs.

[Maksold]

@therouv could you please approve my commit?

[therouv]

@Maksold Thank you for your contribution. I've made some minor changes and added a recommended folder setup in the readme.

[Maksold]

@therouv Thank you for accepting my PR! ;)