Add `ctf::src::Ctf1MetadataStreamParser` class (TSDL)

Add `ctf::src::Ctf1MetadataStreamParser` class (TSDL)

This patch:

* Adds the `ctf::src::MetadataStreamParser` abstract base class
  to have a common base for CTF 1 and CTF 2 metadata stream parsers.

  Parse a metadata stream section with parseSection() (defers to the
  virtual _parseSection() method).

  Get the resulting, current trace class and metadata stream UUID
  with traceCls() and metadataStreamUuid().

  The constructor accepts an optional self component pointer so that
  parseSection() calls finalizeTraceCls() after calling the
  version-specific _parseSection().

* Adds the `ctf::src::Ctf1MetadataStreamParser` class which is a
  concrete TSDL metadata stream parser inheriting
  `ctf::src::MetadataStreamParser`.

  parseSection() requires one or more complete root blocks of TSDL
  contents.

  `ctf::src::Ctf1MetadataStreamParser` also implements the static
  ctf::src::Ctf1MetadataStreamParser::parse() which considers a whole
  metadata stream. While this static method currently doesn't add
  anything to creating a parser and calling parseSection() once, it
  could eventually contain more validation knowing that the metadata
  stream was completely parsed.

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: I55e0f2f05d64a0acc5949029e315aeefae424dda
Reviewed-on: https://review.lttng.org/c/babeltrace/+/8000
Reviewed-by: Philippe Proulx <eeppeliteloop@gmail.com>
Change-Id: I24e175447f759220de5943ccb49c7888a5934ce5