feat(allow-scripts): generate & ship typescript declarations

This adds `.d.ts` generation to `@lavamoat/allow-scripts`.

- Many type defs added to `src/types` for those modules which do not have them (nor are there any published to DefinitelyTyped).  In the future, some of these could be submitted to DefinitelyTyped, if we wish.
- Upgrade `yargs`
- Create reusable TS configuration supporting incremental builds
- Declaration files generated at build time and shipped in the `types` folder (which is now in `.gitignore`)
- Created `.depcheckrc`
- Added, updated, removed and/or fixed many docstring types

Note: the uncommon `skipLibCheck = false` setting in this module's `tsconfig.json` enables typechecking of the `.d.ts` files themselves.  These files are not compiled.

.gitignore

@@ -115,5 +115,7 @@ temp/
 # JetBrains
 .idea
 
+packages/allow-scripts/types
+
 # VScode
 .vscode

config/tsconfig.base.json

@@ -0,0 +1,13 @@
+{
+  "compilerOptions": {
+    "allowJs": true,
+    "allowSyntheticDefaultImports": true,
+    "checkJs": true,
+    "declaration": true,
+    "declarationMap": true,
+    "emitDeclarationOnly": true,
+    "composite": true,
+    "types": ["node"]
+  },
+  "extends": "@tsconfig/node14/tsconfig.json"
+}