Added IPNS keys settings option

[spylogsster]

Second part of brave/brave-browser#15422
First part here #8609

• Added option to IPFS settings that links to keys management subpage, the option is visible only if local node is enabled
• Added APIs to add/remove/fetch keys from node, available only on settings page
• Added observers to switch UI when the node state changed (launch/shutdown)
• Added automatic redirect if current mode is not local node
• Added opportunity to launch node if it is stopped
• Added error indicator if node launch failed. Error message contains the link to open brave://ipfs page for error diagnostic

Normal mode

Node is not launched

Unable to start node

Submitter Checklist:

• I confirm that no security/privacy review is needed, or that I have requested one
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

• Go to brave://ipfs and use option to add/remove keys
• The item to setup IPNS keys should be visible only if current method is local node and the node is launched
• Try to start/stop node when the add/remove key dialog is opened, the dialog should be closed automatically and the button to start node should be shown
• Try to open brave://settings/ipfs/keys page when the node is not installed.
  - If current method is local node you should be asked to start the node and see launch error. There's a linked text that can be clicked to navigate to new brave://ipfs tab
  - If current method is not local node you must be redirected to brave://ipfs
• if you start node from keys page, UIs block to start node and to add keys should be switched automatically

[bbondy]

Things that still need addressing:

• API Permissions fixing

• When testing it I noticed that when I reload brave://settings/ipfs and I click on:
  Setup your IPNS keys it does a refresh on the page and doesn't work until I click it a second time.

• When I was testing it I clicked to add a key but got this in the console Unchecked runtime.lastError: IPFS node is not launched. No error message was displayed though in the page. I didn't have a node installed yet on my local node. We should only show this section when local node is selected in preferences and a node is installed.

• After it is installed but I restart the browser so the node isn't running, I get Unchecked runtime.lastError: Unable to create key. In this case I think it should start the already installed node.

[spylogsster]

Things that still need addressing:

• API Permissions fixing
• When testing it I noticed that when I reload brave://settings/ipfs and I click on:
  Setup your IPNS keys it does a refresh on the page and doesn't work until I click it a second time.
• When I was testing it I clicked to add a key but got this in the console Unchecked runtime.lastError: IPFS node is not launched. No error message was displayed though in the page. I didn't have a node installed yet on my local node. We should only show this section when local node is selected in preferences and a node is installed.
• After it is installed but I restart the browser so the node isn't running, I get Unchecked runtime.lastError: Unable to create key. In this case I think it should start the already installed node.

done

[lidel]

Writing down things from today's sync (could be extracted into separate PRs / issues)

• Add Import and Export buttons to load/save keypair files via ipfs key import|export
• Add ability to rotate self key via ipfs key rotate
  • ipfs key rotate -o self.old.FOO may improve UX a bit (FOO could be lat 4 characters of old key)
  • self key rotation could be also added to brave:ipfs page as a privacy feature to "Rotate Peer Identity (PeerID)`