[TS/JS] New gen TS code gen (#6302)

* TS/ES6 modules spike iteration 1

* Initial modularized dasherized output

* Remove obsoleted parts and namespace wrapping

* Use _flatbuffers_ prefix

* First part of imports logic

* Second part of imports logic

* Fix TS/JS code removal mixup

* Alias imported symbols if same name from different namespaces and some fixes

* Use star import for bare imports

* Fix messed up string concat

* var to const and remove not needed semi

* Remove some cases of ns prefixing

* Add missing space

* Cleanups

* Completed initial import tracking logic

* Compilable output

* Adjust TypeScriptTest and dependents to work

* Use local flatbuffers package for tests

* Refactor away use of any

* Remove obsolete imported_fileset and reexport_map

* Still need any and fix JavaScriptTest.sh

* Fix test runs out of the box

* Temp add generated files

* TypeScriptTest replaces JavaScriptTest and cleanups

* Also remove reference to JavaScriptTest in TestAll.sh

* Remove old generated ts/js files

* Remove use of --js in generate_code scripts

* idl_gen_js_ts to idl_gen_ts and removal of js gen

* Remove obsoleted options

* Fix obsolete ts test detection

* Tweak ts compilation be as strict as possible

* Remove jsdoc type annotation generation

* Generated test ts files

* Fix search and replace messup

* Regenerated ts test output

* Use CharToLower

* Use normal for loop

* Rework namespacedir

* Revert "Rework namespacedir"

This reverts commit 6f4eb0104ceeb86011bb076ebca901138c48e068.

* Revert "Use normal for loop"

This reverts commit 676b2135bfaa1853dfbb06c92b5c16a0d81bb13a.

* Revert "Use CharToLower"

This reverts commit 2d08648d0d72d0af201fad80d54cdc76412b35e9.

* Again do rework but correct

* Avoid runtime cast

* Fix test runs

* Also add npm install to get tsc

* Bump node test versions

* for range to std for loop

* Clang format

* Missed one clang format

* Move accessor to later

* Attempt to make windows version of TypeScriptTest

* Want to see the output

* Try to get newer node at appveyor

* Style changes

docs/source/Compiler.md

@@ -150,16 +150,6 @@ Additional options:
 
 -   `--object-suffix` : Customise class suffix for C++ object-based API.
 
--   `--no-js-exports` : Removes Node.js style export lines (useful for JS)
-
--   `--goog-js-export` :  Uses goog.exportsSymbol and goog.exportsProperty
-    instead of Node.js style exporting.  Needed for compatibility with the
-    Google closure compiler (useful for JS).
-
--   `--es6-js-export` : Generates ECMAScript v6 style export definitions
-    instead of Node.js style exporting. Useful when integrating flatbuffers
-    with modern Javascript projects.
-
 -   `--go-namespace` : Generate the overrided namespace in Golang.
 
 -   `--go-import` : Generate the overrided import for flatbuffers in Golang.
@@ -207,12 +197,6 @@ Additional options:
 
 -   `--keep-prefix` : Keep original prefix of schema include statement.
 
--   `--no-fb-import` : Don't include flatbuffers import statement for TypeScript.
-
--   `--no-ts-reexport` : Don't re-export imported dependencies for TypeScript.
-
--   `--short-names` : Use short function names for JS and TypeScript.
-
 -   `--reflect-types` : Add minimal type reflection to code generation.
 
 -   `--reflect-names` : Add minimal type/name reflection.

docs/source/TypeScriptUsage.md

@@ -70,8 +70,6 @@ For times when efficiency is less important a more convenient object based API
 can be used (through `--gen-object-api`) that is able to unpack & pack a
 FlatBuffer into objects and standard TS types.
 
-**When using the obj based API, the flatbuffers import need to be in the global namespace if you don't have `--no-fb-import` enabled** since creating default values require accessing the `flatbuffers.js` file.
-
 To use:
 
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~{.ts}