IP-XACT frontend and backend for Cerata

This issue was taken from [here](https://github.com/abs-tudelft/fletcher/issues/114) in the Fletcher repo, before it was split up:

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The goal is to build a Cerata frontend and backend for [IP-XACT](https://en.wikipedia.org/wiki/IP-XACT).

The frontend should parse an IP-XACT package to Cerata graphs, and the backend should allow bundling Cerata graph's into an IP-XACT package.

More info on IP-XACT
[Info](https://www.accellera.org/downloads/standards/ip-xact)
[Schema's](http://www.accellera.org/XMLSchema/IPXACT/1685-2014/)
[User guide](https://www.accellera.org/images/downloads/standards/ip-xact/IP-XACT_User_Guide_2018-02-16.pdf)
[kactus2](http://funbase.cs.tut.fi/#ipxact)
[kactus2-code](https://github.com/kactus2/kactus2dev/tree/master/IPXACTmodels)

The issue describes building a frontend to parse IP-XACT packages into Cerata graphs and a backend to bundle graphs into IP-XACT packages. Start by examining the existing Cerata codebase for frontend/backend patterns, review the linked IP-XACT schemas and user guide, and look at the kactus2 code for reference. Determine the entry points for graph construction and serialization in Cerata.

Escrita pelo modelo de indexação a partir do texto da issue.