Self report frame

[sittr7]

Issue #57

Creates frame at takes in user's text input [textbox] and user's certainty of previous answer [likert]

• constants.js and sample_app.js: added self_report strings (including template, questions, and qualifier for likert)
• test_frames.js and test_dbt_worksheet_model.js: added test for displaying this frame
• test_model.html and test_frames.html: added self_report.js into file
• dbt_worksheet_model.js: added a method to build self_report frame and toggle for optional display
• nav.js: added this frame in FrameFactory class

• frames.css: minor styling of likert scale and textbox 🎨

  self_report.js: render() features:

• title (TBD)
• question 1 with textbox as answer input 🔠
• question 2 with likert scale as answer input 🔘

_get_userinput():

• format: _'question1_text': 'textbox values', 'question2text': 'likert answer',