Lstmcpipe

lstmcpipe v0.7 introduces a new workflow to deal with complex pipelines. These changes were necessary to deal with the AllSky MC production.

In particular, stages input and output are provided for each stage through the configuration (instead of being fixed by the directory structure at LA Palma as done until now).
In order to generate such complex configurations, we introduce a new submodule `paths_config` with `PathConfig` classes to deal with the logical structure for each productions.

Working version with:

- `HiPeRTA` [v4.0.0-dev](https://gitlab.in2p3.fr/CTA-LAPP/HiPeRTA/-/tags/v4.0.0-dev)
- `HiPeRTA` uses `hdf5-R0` files converted from `simtel` by using `ctapipe_io_mchdf5` [v0.3.1-dev](https://github.com/cta-observatory/ctapipe_io_mchdf5/releases/tag/v0.3.1-dev)

Added MC prod config for the collaboration

Working version with:

Introduces template for MC productions user requests. Small bugfixes.

Working version with:

- `HiPeRTA` [commit 31/08/2020; 95124004e15638b21734dc8e96dd7d059d2945ce](https://gitlab.in2p3.fr/CTA-LAPP/HiPeRTA/-/tree/95124004e15638b21734dc8e96dd7d059d2945ce)

- HiPeRTA [commit f26cc2f3d2f127ee96ca7638572aa375a6137b24](https://gitlab.in2p3.fr/CTA-LAPP/HiPeRTA/-/tree/f26cc2f3d2f127ee96ca7638572aa375a6137b24)