Improved rsn normalization

[incinn]

• adds a shared normalize_rsn method
• adds get_member_by_rsn method to member service to find member from normalized rsn
• adds tests
• fixes check command for members with a hyphen or underscore in their rsn
• fixes absentee check for members with a hyphen or underscore in their rsn
• fixes activity check for members with a hyphen or underscore in their rsn
• fixes discrepancy check for members with a hyphen or underscore in their rsn

resolves #228