Updates the look and feel of the two (experimental and disabled by
default) links to student records.
Also converts the 'student_records' waffle switch to a waffle flag
named 'credentials.student_records.
LEARNER-5246
Add some waffle-guarded connection points to the Credentials service
to start filling out the user flow for Student Records.
Specifically, add a button to the Program Progress Details page if
a certificate exists, and add a link in the Learner Profile page.
Both only appear if the 'student_records' waffle switch is active.
LEARNER-4701
LEARNER-2485
1) Joined Date is shown in bold and there is no line below to separate
it from the next section.
2) The bio shows up below the certificates.
3) Switching to 'limited profile' does not correctly hide the language,
location and joined date fields.
