[Feature] Directory support for amber build

[siba-dev]

Is your feature request related to a problem? Please describe.
I have a bunch of amber files in a directory i would like to build at once.

Describe the solution you'd like
Amber build command accepting in and optionally an output directory.
Shell scripts should be placed:

• Next to the Amber files with changed extension if no output directory is provided.
• Inside the output directory relative to input path with changed extension.

Describe alternatives you've considered
Simple script finding Amber files and building them one by one is working fine.
Would be cool if it were supported natively.

I would be happy to try and integrate it myself.