Sphinx doc

[v01dXYZ]

This MR proposes an alternative to the current documentation with another one that uses Sphinx and breathe.

Currently breathe needs a patch to fully support all the function signatures as arguments to the directives. I am waiting for the status of my suggested patch to breathe to get merged.

There could be some typos and a need to improve style and readability.

Edit: @Maetveis found a workaround to breathe deficiencies by using doxygengroup (although it does not generate signature with function names starting with ``rocprim::`).

[saadrahim]

Let's get this building on readthedocs. We can enable builds for PRs.

[saadrahim]

This MR proposes an alternative to the current documentation with another one that uses Sphinx and breathe.

Currently breathe needs a patch to fully support all the function signatures as arguments to the directives. I am waiting for the status of my suggested patch to breathe to get merged.

There could be some typos and a need to improve style and readability.

Thank you for the contribution. The rocPRIM team will look into this PR.

[saadrahim]

For consistency, I will raise a PR against this to bring some changes to standardize our sphinx/breathe invocation to the other libraries in our team.

[saadrahim]

@Maetveis @stanleytsang-amd Can this PR be prioritized?

[saadrahim]

closing in favor of #418