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/README.md

@@ -0,0 +1,19 @@
+# ROCprofiler Documentation
+
+## Build Instructions
+
+1. Install conda
+    - `wget https://repo.continuum.io/miniconda/Miniconda3-latest-Linux-x86_64.sh -O miniconda.sh`
+    - `bash miniconda.sh -b -p /opt/conda`
+    - `export PATH=${PATH}:/opt/conda`
+2. Install conda environment
+    - `source activate`
+    - `conda env create -n rocprofiler-docs -f environment.yml`
+    - `conda activate rocprofiler-docs`
+3. Build the docs
+    - `../scripts/update-docs.sh`
+    - HTML docs will be located in `_build/html`
+
+## Developer Information
+
+If you create a new page, add the name of the new markdown file (without extension) to the [index.md](index.md) file.