* merge v3 to v4

* src/components/IconFont

* src/components/PageLoading

* src/components/SelectLang

* src/components/SettingDrawer

* remove e2e and test

* src/components/TopNavHeader

* src/components/GlobalHeader

* src/components/HeaderDropdown

* src/components/HeaderSearch

* src/components/TopNavHeader

* fix error

* mock

* move defaultSettings

* global.txs

* src/locales

* remove lint mock

* fix ci test error

* change PureComponent to Component, interface IDefaultSettings

* Don't prefix interface with I
Close: #3706

* strictNullChecks set true