Update the readme to reference the Bioconductor publication

* Installation instructions should suggest using `BiocManager` instead of installing from GitHub
* We should add the BioC badges: ![](https://bioconductor.org/shields/years-in-bioc/CuratedAtlasQueryR.svg) and/or ![](https://bioconductor.org/shields/build/release/bioc/CuratedAtlasQueryR.svg).