integrate apple silicon instructions in templated install instructions

For example, as described [here](https://develop.qiime2.org/en/latest/plugins/how-to-guides/set-up-development-environment.html#setup-dev-environment). 

For me, this looks like:

```shell
CONDA_SUBDIR=osx-64 conda env create -n q2-hello-world-dev --file ./environment-files/q2-hello-world-qiime2-tiny-dev.yml
conda activate q2-hello-world-dev
conda config --env --set subdir osx-64
```