Delete recent blocks controller

[rekmarks]

Motivation

We had already stopped polling for blocks on default (Infura) networks, and it was recently decided that we would stop doing it on custom (manually entered RPC endpoint) networks as well.

After removing all polling from the recent blocks controller, that controller no longer served any purpose, so it and all its related state has been deleted.

Changes in Detail

• All references to recentBlocks have been deleted from the UI and background.
  • As far as I can tell, recent block data was used for gas price estimation in the transaction controller, but that data appears to have been mostly useless since we stopped polling with recent-blocks - dont listen for block when on infura providers #6124.
  • recentBlocks was also used in the UI, but not in any apparently useful way.
• This PR requires no migration because we stopped persisting recentBlocks in remove BlacklistController from disk state #3148.
• percentile is deleted from the direct dependencies, because all uses of it have been removed.

Future Considerations

We should consider adding an eth_gasPrice call in the transaction retry flow, but that should probably be done in a follow-up PR.

[metamaskbot]

Builds ready [becb810]

• builds: chrome, firefox, opera
• bundle viz: background, ui, inpage, contentscript, ui-libs, bg-libs, phishing-detect
• dep viz: background
• all artifacts

Page Load Metrics (625 ± 54 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	33	100	43	18	9
		domContentLoaded	402	782	623	112	54
		load	404	784	625	111	54
		domInteractive	402	782	623	112	54

[metamaskbot]

Builds ready [b6147bf]

• builds: chrome, firefox, opera
• bundle viz: background, ui, inpage, contentscript, ui-libs, bg-libs, phishing-detect
• dep viz: background
• all artifacts

Page Load Metrics (590 ± 66 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	29	84	43	17	8
		domContentLoaded	338	879	588	137	66
		load	339	880	590	137	66
		domInteractive	337	879	588	137	66

[Gudahtt]

LGTM, great find!