Adding a helper script for Bzlmod migration. (#74)

* Adding a helper script for Bzlmod migration.

The script does the following things:
  - 1. Run the build without Bzlmod enabled to generate resolved external
    dependencies with --experimental_repository_resolved_file
  - 2. Run the build with Bzlmod enabled and identify recongnized error message
  - 3. Use the resolved external deps info to give migration suggestions.
  - 4. Repeat 2 and 3 until all external deps are available via Bzlmod (or WORKSPACE.bzlmod).

To start the migration, clone the Bazel central registry repo and run the following command from your project root:
```
<path to a local BCR repo>/tools/migrate_to_bzlmod.py <build flags> <build targets>
```

* More fixes

* Rename function

* Address comments

tools/add_module.py

@@ -40,12 +40,15 @@
 import sys
 import time
 
-from colorama import Fore, Style
 from registry import Module
 from registry import RegistryClient
 from registry import log
 
 
+YELLOW = "\x1b[33m"
+RESET = "\x1b[0m"
+
+
 def yes_or_no(question, default):
   if default:
     question += " [Y/n]: "
@@ -67,7 +70,7 @@ def yes_or_no(question, default):
 
 
 def ask_input(msg):
-  return input(f"{Fore.YELLOW}ACTION: {Style.RESET_ALL}{msg}")
+  return input(f"{YELLOW}ACTION: {RESET}{msg}")
 
 
 def from_user_input():
@@ -123,7 +126,8 @@ def from_user_input():
           module.add_build_target(target)
 
     if yes_or_no("Do you have a test module in your source archive?", True):
-      module.test_module_path = ask_input("Please enter the test module path in your source archive: ")
+      module.test_module_path = ask_input(
+          "Please enter the test module path in your source archive: ")
       first = True
       while not (module.test_module_build_targets or module.test_module_test_targets):
         if not first: