DOT D&A binder: add driver enrollment guidance + Form G roster

Customers (the DER) had no concrete how-to for onboarding/enrolling drivers or
what information to collect. Add:
- Section 1 'Enrolling a driver (new-hire onboarding)' subsection: exact info to
  collect, the onboarding sequence (collect info, sign Forms A/B, Clearinghouse
  query, prior-employer inquiry, add to C-TPA pool, pre-employment test, wait for
  MRO negative), and a driver-removal note.
- Form G — Driver Enrollment & Covered-Employee Roster: per-driver enrollment
  block (name, DOB, SSN last4, CDL #/state, contact, hire date, test result,
  Clearinghouse/prior-employer status) plus a roster table for the covered pool.
- TOC, email, and handler text updated A-F -> A-G.

scripts/workers/services/dot_drug_alcohol.py

@@ -7,7 +7,7 @@ automatically (no admin step). DOCX is used so the carrier and its counsel
 can review and adapt the program before adopting it. The binder bundles the
 written testing policy, program-management instructions, supervisor-training
 materials and access, EAP / rehab / SAP resources, regulation citations,
-random-testing instructions, all required forms (A-F, each on its own page),
+random-testing instructions, all required forms (A-G, each on its own page),
 and recordkeeping guidance.
 
 Policy variant (DOT operating administration) selection: