Consolidate installation instructions

[Aariq]

Currently there are installation instructions in multiple places in the documentation. This makes the documentation difficult to maintain. For example, docker installation instructions are in three places:

• https://pecanproject.github.io/pecan-documentation/develop/install-docker.html
• https://pecanproject.github.io/pecan-documentation/develop/docker-quickstart.html
• https://pecanproject.github.io/pecan-documentation/develop/the-pecan-docker-install-process-in-detail.html

Two of them are out of date. It would be easier to maintain if all install instructions were consolidated and just linked to in different parts of the documentation where needed.

[Aariq]

There's also docker install instructions in DEV-INTRO.md

[github-actions]

This issue is stale because it has been open 365 days with no activity.

[infotroph]

Unstaling this -- it's still the case and still causing friction for new users 😞

If you're reading this because you Just Wanna Get PEcAn Running, I recommend starting with DEV-INTRO.md whether or not you expect your use case to count as "development."