Move our deps to devDependencies

This is a significant change. Instead of relying on the user to install @bazel/typescript and get
our dependencies installed in their node_modules directory, we install our own hermetic node_modules
in an external workspace using the new npm_install rule introduced in
https://github.com/bazelbuild/rules_nodejs/pull/67

Fixes #88
Fixes #64

This also means we use our own TypeScript compiler to compile
tsc_wrapped. Users are free to use any later TypeScript version to
compile their own code.

Fixes #48

BREAKING CHANGE:

Users now need to load and run the ts_repositories() repository rule.

Closes #95

PiperOrigin-RevId: 178154542