MB-49557 [BP] Don't leak cookie in master-password

Instead set it as an enviornment variable and use `-eval` to set it from
the variable.

This is a backport of MB-48206.

Change-Id: I453dcc7d62995cc4dd91792e69eda68c100a9b53
Reviewed-on: https://review.couchbase.org/c/couchbase-cli/+/172295
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: James Lee <james.lee@couchbase.com>
Well-Formed: Restriction Checker
Reviewed-on: https://review.couchbase.org/c/couchbase-cli/+/172451

Author: matthallcb

cbmgr.py

@@ -1550,11 +1550,12 @@ def prompt_for_master_pwd(self, node, cookie, password, cb_cfg_path):
 
         name = 'executioner@cb.local'
         args = ['-pa', CB_NS_EBIN_PATH, CB_BABYSITTER_EBIN_PATH, '-noinput', '-name', name, '-proto_dist', 'cb',
-                '-epmd_module', 'cb_epmd', '-kernel'] + CB_INETRC_OPT + \
-            ['dist_config_file', f'"{dist_cfg_file}"', '-setcookie', cookie, '-run', 'encryption_service',
+                '-eval', 'erlang:set_cookie(list_to_atom(os:getenv("CB_COOKIE"))).', '-epmd_module', 'cb_epmd',
+                '-kernel'] + CB_INETRC_OPT + \
+            ['dist_config_file', f'"{dist_cfg_file}"', '-run', 'encryption_service',
              'remote_set_password', node]
 
-        rc, out, err = self.run_process("erl", args, extra_env={'SETPASSWORD': password})
+        rc, out, err = self.run_process("erl", args, extra_env={'SETPASSWORD': password, 'CB_COOKIE': cookie})
 
         if rc == 0:
             print("SUCCESS: Password accepted. Node started booting.")