feat: save identity data to sf's config and to the server

[sfdctaka]

What does this PR do?

• Saves identity data structure in sf's config
• Saves identity token on server

What issues does this PR fix or reference?

@W-15428971@

[maliroteh-sf]

@sfdctaka and @khawkins

In this PR shouldn't we also update PreviewUtils.generateDesktopPreviewLaunchArguments() and PreviewUtils.generateMobileAppPreviewLaunchArguments() to generate something for 0.aura.ldpServerId?

[sfdctaka]

@sfdctaka and @khawkins

In this PR shouldn't we also update PreviewUtils.generateDesktopPreviewLaunchArguments() and PreviewUtils.generateMobileAppPreviewLaunchArguments() to generate something for 0.aura.ldpServerId?

Aah. Thought desktopPreview(...) and mobilePreview(...) were going to take the token and do that for 0.aura.ldpServerId. I will add it.

[khawkins]

This is sort of a "one of these things is not like the other", in that the rest of the input parameters are more or less directly plugged into the functions of this method, whereas username is indirectly used as a lookup.

Should we retrieve the Entity ID beforehand, and pass that value in as the input parameter?

[khawkins]

Seems like it would be more consistent to look up Entity ID (in some capacity) in app.ts, somewhere around where the ldpServerUrl is determined.

[khawkins]

I think my only outstanding comment was the username lookup, but otherwise this all looks fine to me.