Support tsConfig paths aliases during move operations

[tryggvigy]

Showcases fix for #1494.

Naive support for tsconfig.compilerOptions.paths module specifier aliases during move operations.

const project = new Project({
  useInMemoryFileSystem: true,
  compilerOptions: {
    paths: {
      'Root/*': ['./*']
    }
  }
});

const a = project.createSourceFile("a.ts", `export function foo() {}`);
// b.ts imports `a` via paths mapping alias.
const b = project.createSourceFile("b.ts", `import { foo } from "Root/a";`);

// Move ./a.ts -> ./a./a.ts
const dir = project.createDirectory('./a');
a.moveToDirectory(dir);

// Updating path aliased import works.
expect(b.getFullText()).to.equal(`import { foo } from "Root/a/a";`);

[tryggvigy]

This is very naive right now and only works with wildcard paths (most common use-case afaik). If we want to productionize this approach we should create new helpers in ModuleUtils and/or SourceFile to more deeply support paths aliases, instead of reaching directly for FileUtils here.

[tryggvigy]

If we want to move ahead with this PR we should add a lot more tests for paths.

• With and without wildcard value
• More nested mappings