fix: add strict types to build scripts and remove all any usage

Replace all implicit and explicit any types in build scripts with
proper TypeScript Compiler API types (Decorator, ClassDeclaration,
MethodDeclaration, Identifier, SourceFile, etc.). Add PackageJson
and InjectableClassEntry interfaces. Fix return types, null checks,
and type assertions throughout all transformer scripts.

scripts/build/transformers/extract-injectables.ts

@@ -23,7 +23,7 @@ export const EMIT_PATH = resolve(ROOT, 'injectable-classes.json');
  */
 export function extractInjectables() {
   return (ctx: TransformationContext) => {
-    return (tsSourceFile) => {
+    return (tsSourceFile: any) => {
       if (tsSourceFile.fileName.indexOf('src/@awesome-cordova-plugins/plugins') > -1) {
         visitEachChild(
           tsSourceFile,
@@ -36,7 +36,7 @@ export function extractInjectables() {
             if (isInjectable) {
               injectableClasses.push({
                 file: tsSourceFile.path,
-                className: (node as ClassDeclaration).name.text,
+                className: (node as ClassDeclaration).name!.text,
                 dirName: tsSourceFile.path.split(/[\\\/]+/).reverse()[1],
               });
             }