Improve user agent handling/provide user agent "short" codes

[TheCleric]

So I took a risk with this PR (and probably should have discussed some of this with you first @ronjouch, but I started tugging on the thread of:

How can I get Google (and other apps) to behave better or make it easier for a user to be self-sufficient?

Obviously this has been an ongoing problem, but particularly in this thread, and this comment: #1193 (comment) . Not that there was anything WRONG in this question, it just got me thinking that there has to be a better way.

So this is my attempt at a "better" way. Better being in the eye of the developer though, I'm fine changing some of this until we're both happy.

Here's what I've changed:

• Eliminated the "inferUserAgent" logic, because I realized we can:
• Rely more heavily on Electron's app.userAgentFallback which has a Chrome-like user agent pre-populated in it already, based on the Electron version used. For --honest/--user-agent-honest we'll use it as is. Without that we'll strip out the elements of it that indicate it's not Chrome (Electron/version and GeneratedAppName/version)
• Add short codes that can be passed to --user-agent that will determine the latest versions of some common browsers, and generate a user agent for the user, so they don't have to go hunting one down. Included is support for:
  • edge which will grab the chrome version by electron version like inferUserAgent did, and populate it
  • firefox which will hit the FF versions API and get latest stable and generate a user agent
  • safari which will hit Wikipedia (sorry, it's the only reliable, up to date source I could find) and get the latest version (and WebKit version) and generate a user agent
• Standardize on using userAgentHonest over honest

[ronjouch]

Looks good, I have a couple nits.

"Add short codes [so that users] don't have to go hunting one down"

Great idea 👍

[TheCleric]

Alright @ronjouch I think all nits have been addressed

[ronjouch]

👍:clap: