Improve documentation for initial Conda setup

[lbianchi-lbl]

We should inspect the Sphinx documentation (and anywhere else where Conda is mentioned) and ensure that:

• Miniforge, as opposed to other similar Conda installation solutions such as e.g. Miniconda, is the recommended way to install conda and related tooling (Update docs on use of miniforge #1432)
• The process for installing Miniforge addresses common gotchas, primarily
  • The fact that the wrong version (x86_64 instead of aarch64) might end up getting installed on macOS for Apple Silicon machines (likely cause of Unable to load HSL solvers for IPOPT on M1 Mac #1494)