Enable more eslint-plugin-jest rules by default

[edmorley]

eslint-plugin-jest has a recommended rule set, which we're not using:
https://github.com/jest-community/eslint-plugin-jest#recommended

neutrino/packages/jest/src/index.js

Lines 18 to 23 in 04ae1d3

	rules: {
	'jest/no-disabled-tests': 'warn',
	'jest/no-focused-tests': 'error',
	'jest/no-identical-title': 'error',
	'jest/valid-expect': 'error'
	}

I think we should use it in @neutrinojs/jest instead of only manually enabling a handful of rules.

Thoughts?

Also the v22 release of eslint-plugin-jest added a new style preset configuration alongside recommended:
jest-community/eslint-plugin-jest#193
https://github.com/jest-community/eslint-plugin-jest#style

Should we use that too?