Add explicit package manager support list and installation instructions

[MikeMcC399]

Description

What would you like?

1. Add a section for Package Manager in the Get Started > Install Cypress > System requirements section
2. Add the following list of supported package managers:
   • npm 8.6.0 and above (corresponds to npm version packaged with Node.js 18.0.0)
   • Yarn Classic 1.22.22 and above
   • Yarn Modern 4.x and above
     for Component testing, with nodeLinker: "node-modules" configuration only
   • pnpm 8.x and above
3. Move any generic installation instructions, which are not Cypress specific, down to this section.
4. Separate out Cypress-specific installation instructions and keep these in the Get Started > Install Cypress section.

Why is this needed?

1. Although npm, Yarn and pnpm are listed as supported, there is no information about which versions are supported.
2. Descriptions in Get Started > Install Cypress mix up the reference to specific package managers. Generic and Cypress-specific instructions are put together instead of being clearly separated.
3. Yarn Classic and Yarn Modern are different products with a combination of similarities and major incompatibilities, so it is not clear, when referring to Yarn, whether Yarn Classic or Yarn Modern or both are meant.
4. Instructions for how to install Yarn are missing. If these instructions are added, they should take account of the fact that Yarn 1 Classic and Yarn Modern are to be installed differently from each other.
5. Instructions for how to install pnpm using npm are incorrect if Corepack is enabled. Refer to pnpm Installation for full instructions.

Other

Related to:

• Yarn Modern Plug'n'Play incompatibility with CT missing in docs #5394

[MikeMcC399]

@jennifer-shehane

I plan to submit a PR to implement the above suggestions.

[MikeMcC399]

• See PR Add package manager list and installation instructions #6093