Refactor get user field

[angaither]

Overview

Refactoring calls to dosomething_user_get_field

What does this PR do?

• Creates a generic dosomething_user_get_field function
  • This function calls handlers if more specific formatting is needed
  • The handlers should not be called directly

How to test

• Check out this PR
• Test out the user profile page for any oddities
• Manually drush php-eval functions to make sure the results are as expected, a few to test...
  • drush php-eval "var_dump(dosomething_signup_get_mbp_params(user_load(10), node_load(84)));"
  • drush php-eval "echo dosomething_user_is_under_thirteen(user_load(10))"
  • drush php-eval "echo dosomething_user_get_field('field_first_name', user_load(10), 'ucwords');"

Bonus! Fixes #2606

[aaronschachter]

Minor but I could see us moving this into dosomething_helpers to potentially use in other modules.

[aaronschachter]

Code looks ok - just seemed to find the one bug in the Campaign Close template. Another place we could use this is in the User Signup Form, where we collect addresses, but this is also minor and not needed for merge..

[aaronschachter]

👍