Pinning service integration: Augment "Pin IPFS Resource" functionality

[jessicaschilling]

Note: This issue is part of a larger pinning service integration epic undertaken spring/summer 2020.

The need

Augment functionality of existing "Pin IPFS Resource" toggle to support the use of third-party pinning services:

• Keep UI of existing "Pin IPFS Resource" toggle as-is (don't break UX for people who are used to "pinning via Companion")
• When a resource is not pinned, and the toggle is clicked, in addition to creating low-level pin (current behavior), it also imports to MFS and opens imported resource in the same UI as "Quick Import" (e.g. takes you to appropriate page in Files screen)

Context

Advantages of this approach are:

• works the same as importing non-IPFS data, reducing cognitive overhead
• they can immediately manage imported resource via UI on webui's Files screen
• works fine even if user pins entire wikipedia (lazy-loading, only pages they actually visited are kept around)

Original note from PRD:

(TBD) Feature in IPFS Companion that allows a user to pin data to their chosen pinning service

• This is likely unnecessary with auto-upload rules for pinned files

User flow:

• Users can use Desktop or WebUI to connect their local node to an IPFS pinning service
• User right-clicks a file or image and selects “pin to IPFS”
• If they have an auto-upload rule configured, that file is automatically added to their associated pinning service

[jessicaschilling]

@lidel and @rafaelramalho19 --

AFAIK, there are two scenarios in which a Companion user might invoke third-party pinning. Both only occur if the user has "Auto upload" enabled for one or more pinning services.

1. From the "Pin IPFS resource" toggle in the Companion drop-down.
   

2. When right-clicking on a page/image and selecting "Import to IPFS".
   

This seems logical enough that it doesn't need any modification or explanation, but want to run that past you both to make sure (a) that I haven't omitted any possible scenarios (b) it doesn't feel logical/obvious to you. Thanks!

[lidel]

• 👍 Flow for (2) "Import to IPFS" is already ending in Web UI, so I don't think we need to do anything there.

• ❓ Depending on how pinning service integration is implemented, "pinning current URL" (1) may be problematic. If "auto pinning" requires webui running to work, then the existing toggle won't trigger pinning at remote service. We may rewire this toggle to open "pinning screen" in webui instead.