Batch mode

[jcordes73]

It would be great to have a "batch mode" for toolbox, i.e.

3scale batch

This should improve the overall experience and performance when using the toolbox for multiple operations as

• Firing up a container for each operation is time-consuming
• Establishing SSL/TLS handshakes is a costly operation
• Multiple commands could be run over the same HTTP connection (via keepalive) leading to lower latency