Push multiple packages

### 1. Request

It would be nice, if will be possible push multiple packages to Chocolatey remote server.

### 2. Justification

One-by-one push may spend a lot of time, if maintainer have a lot of packages.

### 3. Desirable behavior

For example, I create and/or upgrade multiple packages. [**I tested all my packages**](https://gist.github.com/Kristinita/8d35c6a73b8c1e678dce675556819915).

All my packages I save in `D:\SashaChocolatey\packages` folder in my local machine. I run terminal in `D:\SashaChocolatey\packages` folder → `choco push all` →

+ if package in current version already exists, choco skip it;
+ if package new of upgraded, choco push it.

Thanks.

Start by tracing the `choco push` command used from the packages directory and how it handles a single package on the Chocolatey remote server. The change is done when a command such as `choco push all` can process packages in the current directory, skip versions already present, and push new or upgraded packages.

Written by the indexing model from the issue text.