[redesign] Launcher views

[bgptr]

Builds upon #3669
Requires decred/pi-ui#417 has been merged
Closes #3614

Notes:

• add onboarding tutorials to the launcher.
• add gradients to the wallet cards. One gradient is connected to an exact wallet and saved to the config. After using the 11 predefined gradients, extra gradients are generated on the fly. The logic is simple: take a random color and create a gradient with the opposite color on the color wheel.
• move the redesigned progress bar to the bottom. In order for the progress bar could be displayed in the nested pages (after clicking one of the top links) the getstarted state machine revamped a bit: the settings, logs, release info have been ditched and controlled the visibility from the GetStartedPage/hooks.js. Same with the new onboarding tutorial pages.
• ditch RescanWallet component. The rescan progress is integrated now into the progress bar and the onboarding tutorials list is displayed during the progress.
• introduce a new progress bar indication of the fetching block headers process.
• add Setup a Trezor Wallet, but it depends on [redesign] Trezor views #3570
• add Automated Wallet Launching modal and save the answer to the config. It can not be changed from the Settings yet. Planned to implement it after [redesign] Settings view #3631 will be merged. It can be toggled from the Settings now.

Updated screenshots:

[matheusd]

This is looking pretty slick!

UX wise, my only comment is that, after the initial sync process is done, the "Open Wallet" button looks a bit timid: I didn't realize I had to click it to continue opening the wallet.

Also, the "automatically load wallet" doesn't seem to work if you close the wallet (settings -> close wallet) and then try to open it again. It only works after an app reload.

These seem very minor, so i'm ok with merging this as is then working through the issues in an ongoing fashion.