Add Cypress utility methods for OS / Platform / Arch / Browser / Browser Version

[brian-mann]

Something like this...

// utility functions
Cypress.isPlatform()
Cypress.isBrowser()
Cypress.isArch()
Cypress.isBrowserVersion()

// constants
Cypress.arch
Cypress.platform
Cypress.browser
Cypress.browserVersion

Cypress.isWindows()
Cypress.isLinux()
Cypress.isMac()

if (Cypress.browser === "chrome") {

}

if (Cypress.isPlatform(["win32", "darwin"]) {

})

if (!Cypress.isBrowser("firefox") {

}

What about normalizing things like chrome, chromium, canary ?

[bahmutov]

I really think we should split this into platform + arch vs browser and for now just do the first part - this is needed to correctly test cy.exec for example.

When adding any functions must update cypress/cli/index.d.ts too

[brian-mann]

Fixed by #986