ISSUE-3: Refactored PEP parsing logic into a model class
ISSUE-3: Added PEP Plain Text Documents
ISSUE-3: Added PEP model

Instead of parsing from HTML PEP document, plaintext PEP document was
used to parse metatdata out of the document.

ADD: Added Unit tests for PEP
ISSUE#3: Added E2E test
ISSUE#3: Added to_dict method on PEP
ISSUE#3: Added PEP metadata to API
ISSUE#3: Moved unit tests into a folder
Merge branch 'issue-3' into dev