Pro HTTP client updates

[atavism]

Depends on getlantern/flashlight#1371

• Remove use of flashlight/pro/client: https://github.com/getlantern/flashlight/compare/atavism/remove-pro-client?expand=1
• Use go-resty-based HTTP client for interacting with Pro server
• Add protobuf messages for Pro API requests and responses

[atavism]

@atavism have you completed your testing?

@jigar-f I just finished testing desktop and fixed a couple issues (such as the formatted monthly cost missing from plans for instance). Now the full checkout flow is working for me again (plans -> payment methods -> payment redirect).

I'll test Android in the morning.

[jigar-f]

@atavism Just a thought, Do you think we decouple proclient? So later on we can use that for Android and IOS as well, At the moment it looks like it is tightly coupled with desktop code, Maybe can create some custom interface and pass that NewClient so we can use it for desktop and android and IOS as well.

[jigar-f]

LGTM, Just some comments.

[jigar-f]

@atavism

• I do not see a loading bar when doing the Reseller checkout
• When I click authorize device with Link with PIN It doesn't show the PIN

[atavism]

@atavism Just a thought, Do you think we decouple proclient? So later on we can use that for Android and IOS as well, At the moment it looks like it is tightly coupled with desktop code, Maybe can create some custom interface and pass that NewClient so we can use it for desktop and android and IOS as well.

That definitely makes sense. Making some changes now to no longer pass settings to ProClient

[atavism]

Maybe can create some custom interface and pass that NewClient so we can use it for desktop and android and IOS as well.

This is done. Updating iOS to use it now.

[atavism]

I do not see a loading bar when doing the Reseller checkout
When I click authorize device with Link with PIN It doesn't show the PIN

The device name was missing requesting a linking code:

{"status":"error","error":"Bad input: request missing Device Name","errorId":"bad-input-missing-device-name","Code":"","ExpireAt":0}

Should be fixed now.

[atavism]

Maybe can create some custom interface and pass that NewClient so we can use it for desktop and android and IOS as well.

iOS is using the new Pro client now.

For Android, the changes are more extensive than I anticipated since we have to get rid of the LanternHttpClient. I opened a ticket for that.