[TS/JS] Entry point per namespace and reworked 1.x compatible single file build (#7510)

* [TS/JS] Entry point per namespace

* Fix handling of outputpath and array_test

* Attempt to fix generate_code

* Fix cwd for ts in generate_code

* Attempt to fixup bazel and some docs

* Add --ts-flat-files to bazel build to get bundle

* Move to DEFAULT_FLATC_TS_ARGS

* Attempt to add esbuild

* Attempt to use npm instead

* Remove futile attempt to add esbuild

* Attempt to as bazel esbuild

* Shuffle

* Upgrade bazel deps

* Revert failed attempts to get bazel working

* Ignore flatc tests for now

* Add esbuild dependency

* `package.json` Include esbuild

* `WORKSPACE` Add fetching esbuild binary

* Update WORKSPACE

* Unfreeze Lockfile

* Update WORKSPACE

* Update BUILD.bazel

* Rework to suggest instead of running external bundler

* Add esbuild generation to test script

* Prelim bundle test

* Run test JavaScriptTest from flatbuffers 1.x

* Deps upgrade

* Clang format fix

* Revert bazel changes

* Fix newline

* Generate with type declarations

* Handle "empty" root namespace

* Adjust tests for typescript_keywords.ts

* Separate test procedure for old node resolution module output

* Fix rel path for root level re-exports

* Bazel support for esbuild-based flatc

Unfortunately, we lose typing information because the new esbuild method
of generating single files does not generate type information.

The method used here is a bit hack-ish because it relies on parsing the
console output of flatc to figure out what to do.

* Try to fix bazel build for when node isn't present on host

* Auto formatting fixes

* Fix missing generated code

Co-authored-by: Derek Bailey <derekbailey@google.com>
Co-authored-by: James Kuszmaul <jabukuszmaul+collab@gmail.com>

tests/ts/arrays_test_complex/my-game/example/inner-struct.ts

@@ -0,0 +1,91 @@
+// automatically generated by the FlatBuffers compiler, do not modify
+
+import * as flatbuffers from 'flatbuffers';
+
+
+
+export class InnerStruct implements flatbuffers.IUnpackableObject<InnerStructT> {
+  bb: flatbuffers.ByteBuffer|null = null;
+  bb_pos = 0;
+  __init(i:number, bb:flatbuffers.ByteBuffer):InnerStruct {
+  this.bb_pos = i;
+  this.bb = bb;
+  return this;
+}
+
+a():number {
+  return this.bb!.readFloat64(this.bb_pos);
+}
+
+b(index: number):number|null {
+    return this.bb!.readUint8(this.bb_pos + 8 + index);
+}
+
+c():number {
+  return this.bb!.readInt8(this.bb_pos + 21);
+}
+
+dUnderscore():bigint {
+  return this.bb!.readInt64(this.bb_pos + 24);
+}
+
+static getFullyQualifiedName():string {
+  return 'MyGame.Example.InnerStruct';
+}
+
+static sizeOf():number {
+  return 32;
+}
+
+static createInnerStruct(builder:flatbuffers.Builder, a: number, b: number[]|null, c: number, d_underscore: bigint):flatbuffers.Offset {
+  builder.prep(8, 32);
+  builder.writeInt64(BigInt(d_underscore ?? 0));
+  builder.pad(2);
+  builder.writeInt8(c);
+
+  for (let i = 12; i >= 0; --i) {
+    builder.writeInt8((b?.[i] ?? 0));
+
+  }
+
+  builder.writeFloat64(a);
+  return builder.offset();
+}
+
+
+unpack(): InnerStructT {
+  return new InnerStructT(
+    this.a(),
+    this.bb!.createScalarList<number>(this.b.bind(this), 13),
+    this.c(),
+    this.dUnderscore()
+  );
+}
+
+
+unpackTo(_o: InnerStructT): void {
+  _o.a = this.a();
+  _o.b = this.bb!.createScalarList<number>(this.b.bind(this), 13);
+  _o.c = this.c();
+  _o.dUnderscore = this.dUnderscore();
+}
+}
+
+export class InnerStructT implements flatbuffers.IGeneratedObject {
+constructor(
+  public a: number = 0.0,
+  public b: (number)[] = [],
+  public c: number = 0,
+  public dUnderscore: bigint = BigInt('0')
+){}
+
+
+pack(builder:flatbuffers.Builder): flatbuffers.Offset {
+  return InnerStruct.createInnerStruct(builder,
+    this.a,
+    this.b,
+    this.c,
+    this.dUnderscore
+  );
+}
+}