Merge pull request #1796 from ProjectMirador/1585-add-i18next

__tests__/src/components/WindowList.test.js

__tests__/src/components/WindowSideBarButtons.test.js

__tests__/src/components/WindowSideBarInfoPanel.test.js

__tests__/src/components/WindowSideBarPanel.test.js

__tests__/src/components/WindowTopBar.test.js

...sts__/src/components/WorkspaceControlPanelButtons.test.js

__tests__/src/components/WorkspaceFullScreenButton.test.js

__tests__/src/components/WorkspaceMenu.test.js

locales/en/translation.json

package.json

src/components/ManifestForm.js

src/components/WindowList.js

src/components/WindowSideBarButtons.js

src/components/WindowSideBarInfoPanel.js

src/components/WindowSideBarPanel.js

src/components/WindowThumbnailSettings.js

src/components/WindowTopBar.js

src/components/WindowTopMenuButton.js

src/components/WorkspaceAddButton.js

src/components/WorkspaceControlPanelButtons.js