Docs skeleton (#51)

* Add doxygen-awesome-css submodule

* Basic documentation files

- conf.py: run by sphinx
- about.md: info about rocprofiler
- features.md: overview of features
- installation.md: build/test/install instructions
- index.md: sets up main page
- generate-doxyfile.cmake: generates rocprofiler.dox with rocprofiler-specific info
- environment.yml: conda environment
- Makefile: sphinx makefile
- README.md: build instructions
- rocprofiler.dox.in: doxygen template
- .gitignore: ignores generated files
- .nojekyll: prevents GitHub Pages from using Jekyll for deployment of pages

* Documentation scripts

- scripts for doing common sequences of commands for building docs
- update-docs.sh: builds the docs and installs the docs if /docs directory is present
- update-doxygen.sh: quick script for generating doxygen

* Workflow for docs

- step for building docs
- step for deploying docs

* Update doxygen comments in include/rocprofiler

- rocprofiler.h / rocprofiler_plugins.h
  - fixed non-existent global references in doxygen comments
  - fixed parameter names that were incorrect or not updated

* Update docs workflow

- only deploy docs when on main branch

source/docs/Makefile

@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = .
+BUILDDIR      = _build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)