Add Satysfi_autogen library

[na4zagin3]

Satysfi_autogen library has two autogen libraries:

• satyrographos/experimental/fonts: list of installed fonts
• satyrographos/experimental/libraries: list of installed libraries

Those libraries will be used with -a option of install subcommand like:

satyrographos install -a '%libraries' -a '%fonts'

This PR makes it possible to write a font specimen document like https://gist.github.com/na4zagin3/4c9d32cb9659e128cdd35e3f650539bc

This is an initial step of https://github.com/na4zagin3/satyrographos/issues/112