Removes the "Clear all answers" button

[#45072737]
Doing radio-button labels properly
Fixes "Check Answer" to previous state

[#39917671]
Note for TODOs
Getting expected behavior on "custom prompts" checkbox

[#39917671] The pseudo-attribute way of doing this was too cute and wasn't working properly (i.e. not persisting user changes across reloads) so here we'll do it the hard way.
Don't serialize custom MC prompts if they're off

[#39917671]
Making check-answer specs pass
Fixes Run#increment_run_count
Passing test for unique Run hashes (slow)
Obsolete TODO comment
Change run keys to use UUID
Test updates for UUID instead of hashes as run key
portal SSO support
parameterize the url to the concord portal
add email address to the top of the page
fix SSO email handling
code formatting changes
code formatting
Refactor OpenResponseAnswerSpec to use let
Serialization of OR answers to JSON

Starts on [#35529763]: get the saved answers to serialize in the format the portal expects.