chore: add the new policy.json review process documentation and config

[naugtur]

Description

Introducing the document outlining policy review process.

The current change to CODEOWNERS doesn't remove the all devs group - this makes it a soft-launch of the process where a specific approving review is not yet mandatory.

We'll be releasing a training video early January.

After merging this, I'm hoping to reference the document in multiple places to aid people in discovering and following the process.

Related issues

Fixes: lack of attention to policy updates

Manual testing steps

1. Follow the process and experience joy

Screenshots/Recordings

Before

After

Pre-merge author checklist

• I've followed MetaMask Contributor Docs and MetaMask Extension Coding Standards.
• I've completed the PR template to the best of my ability
• I’ve included tests if applicable
• I’ve documented my code using JSDoc format if applicable
• I’ve applied the right labels on the PR (see labeling guidelines). Not required for external contributors.

Pre-merge reviewer checklist

• I've manually tested the PR (e.g. pull and build branch, run the app, test code being changed).
• I confirm that this PR addresses all acceptance criteria described in the ticket it closes and includes the necessary testing evidence such as recordings and or screenshots.

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[metamaskbot]

Builds ready [fe9af48]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Background Module Init Stats
• mv3: UI Init Stats
• mv3: Module Load Stats
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• code coverage: Report
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6
  • common: 0, 1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • offscreen: 0
  • ui: 0, 1, 10, 11, 12, 13, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (1558 ± 59 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1363	2015	1561	132	64
		domContentLoaded	1348	1928	1529	120	58
		load	1367	1962	1558	122	59
		domInteractive	20	85	38	20	10
		backgroundConnect	10	63	29	19	9
		firstReactRender	15	73	32	22	11
		getState	4	49	12	12	6
		initialActions	0	0	0	0	0
		loadScripts	1001	1449	1148	90	43
		setupStore	6	20	8	3	1
		uiStartup	1518	2194	1757	130	62

Bundle size diffs

• background: 0 Bytes (0.00%)
• ui: 0 Bytes (0.00%)
• common: 0 Bytes (0.00%)

[metamaskbot]

Builds ready [4149303]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7
  • common: 0, 1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • offscreen: 0
  • ui: 0, 1, 10, 11, 12, 13, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (1714 ± 61 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1522	1925	1715	123	59
		domContentLoaded	1490	1911	1688	118	57
		load	1496	1928	1714	126	61
		domInteractive	22	200	51	42	20
		backgroundConnect	8	73	29	22	10
		firstReactRender	16	106	56	36	18
		getState	4	75	22	26	12
		initialActions	0	1	0	0	0
		loadScripts	1060	1476	1275	114	55
		setupStore	6	91	26	30	15
		uiStartup	1706	2716	2091	306	147

[naugtur]

Hey, @MetaMask/policy-reviewers would you mind approving the PR that establishes the use of the group? 😄

[Gudahtt]

Looks great! Just one minor correction

[metamaskbot]

Builds ready [bb0fc60]

• builds: chrome, firefox
• builds (beta): chrome
• builds (flask): chrome, firefox
• builds (MMI): chrome, firefox
• builds (test): chrome, firefox
• builds (test-flask): chrome, firefox
• build viz: Build System
• mv3: Bundle Size Stats
• mv2: E2e Actions Stats
• storybook: Storybook
• typescript migration: Dashboard
• all artifacts
• bundle viz:

  • background: 0, 1, 2, 3, 4, 5, 6, 7
  • common: 0, 1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9
  • content-script: 0
  • offscreen: 0
  • ui: 0, 1, 10, 11, 12, 13, 2, 3, 4, 5, 6, 7, 8, 9

Page Load Metrics (1695 ± 68 ms)

Platform	Page	Metric	Min (ms)	Max (ms)	Average (ms)	StandardDeviation (ms)	MarginOfError (ms)
Chrome	Home	firstPaint	1530	2017	1703	136	65
		domContentLoaded	1524	1986	1664	130	62
		load	1529	2023	1695	142	68
		domInteractive	25	98	45	24	12
		backgroundConnect	8	108	33	30	14
		firstReactRender	17	173	49	40	19
		getState	5	86	28	27	13
		initialActions	0	1	0	0	0
		loadScripts	1113	1452	1226	89	43
		setupStore	6	24	9	4	2
		uiStartup	1736	2687	2030	262	126