Add `ctf::src::MetadataStreamParser` class

Add `ctf::src::MetadataStreamParser` class

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The commit message of the old `Add ctf::src::finalizeTraceCls()` commit:

This new function finalizes a `ctf::src` CTF IR trace class after its
creation or when it gets new data stream classes or event record
classes.

The function:

* Sets the value saving indexes of dependencies (field classes) and the
  saved value index of dependent (dynamic-length, optional, and variant)
  field classes.

  It also links the dependent field classes to their dependencies by
  weak pointer.

* With a self component pointer, translates the contained objects to
  their trace IR equivalents.
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Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: I24e175447f759220de5943ccb49c7888a5934ce5
Signed-off-by: Simon Marchi <simon.marchi@efficios.com>