Chore: Migrate packages to TypeScript

[scottrippey]

Prerequisites

• [x] Support TypeScript in builds, tools, etc
• [x] Migrate victory-core and victory-vendor to TS

Motivation

Migrating all other packages to TypeScript will have the following benefits:

• Type-safety for these packages, obviously
• Once we reach 100%, we can drop babel and use tsc directly

Components to migrate

• [x] victory #2319
• [x] victory-area #2314
• [x] victory-axis #2379
• [ ] victory-bar
• [x] victory-box-plot #2387
• [x] victory-brush-container #2393
• [x] victory-brush-line #2393
• [ ] victory-candlestick
• [ ] victory-canvas
• [x] victory-chart #2314
• [ ] victory-create-container
• [ ] victory-cursor-container #2419
• [ ] victory-errorbar
• [x] victory-group #2396
• [ ] victory-histogram
• [ ] victory-legend
• [x] victory-line #2306
• [ ] victory-native
• [ ] victory-pie
• [ ] victory-polar-axis
• [x] victory-scatter #2394
• [ ] victory-selection-container
• [ ] victory-shared-events
• [x] victory-stack #2422
• [ ] victory-tooltip
• [ ] victory-voronoi
• [ ] victory-voronoi-container
• [ ] victory-zoom-container