Profiling infrastructure

[robertodr]

This PR provides documentation and infrastructure for profiling the library. Of the tools I have explored, only gperftools needed some CMake infrastructure. I haven't considered gprof: according to the Internet it's basically deprecated in favor of perf.

The set of input files for benchmarking should definitely be expanded to stress-test different parts of the code.

Todos

• Developer Interest

• Document CPU profiling using perf.
• Document CPU profiling with Google perf tools.
• Document heap profiling with Google perf tools.
• Document profiling using VTune.
• Provide a set of input files for benchmarking.

Types of changes

• New feature (non-breaking change which adds functionality)

Status

• Ready to go

[MinazoBot]

	1 Warning
⚠️	Please update CHANGELOG.md with a description of your changes. If this PR is not a user-facing change (e.g. just refactoring), you can disregard this.

Here's an example of a CHANGELOG.md entry:

* [#136](https://github.com/PCMSolver/pcmsolver/pull/136): Profiling infrastructure - [@robertodr](https://github.com/robertodr)

Generated by 🚫 Danger

[codecov]

Codecov Report

Merging #136 into release/1.2.Z will not change coverage.
The diff coverage is n/a.

@@              Coverage Diff               @@
##           release/1.2.Z     #136   +/-   ##
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  Coverage          69.81%   69.81%           
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  Files                 92       92           
  Lines               5625     5625           
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  Hits                3927     3927           
  Misses              1698     1698

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[bast]

Looks very good. I started using perf after you have recommended and it is indeed a nice tool. The doc here is great.

[robertodr]

Thanks! I'll rebase and then you can push the button.