promote protobuf conformance testing client to main directory

Moving the conformance test runner out of the experimental directory
and refreshing things so we can get a baseline for the current state
of the repo.

This does not exactly represent google-protobuf-3.21.4 because there
was a missing @export annotation that prevents the tests from running
correctly (i.e. function not found in optimized mode).

This change also merges together the runner's main file and helper
library for the sake of simplicity and uses node requires exclusively.
We previously supported running conformance tests in browser mode, but
I'm dropping it for the sake of getting things running.

Author: dibenede

.gitignore

@@ -1,4 +1,5 @@
 .idea
+.vscode
 node_modules
 commonjs_out
 google/protobuf
@@ -7,3 +8,6 @@ bazel-*
 /testproto_libs1.js
 /testproto_libs2.js
 /google-protobuf.js
+/google-protobuf-*.tgz
+/conformance/protos/*.js
+/conformance/package-lock.json

MODULE.bazel.lock

@@ -0,0 +1,29 @@
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+
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+
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+
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+
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