Added the find section by code functionality

[Vortex-21]

Description

I have updated the cdaannotator by adding the _find_section_by_code() function and modifying the related functions such that if the cda document doesn't contain template_ids then it can identify and retrieve the related sections using their respective code values .

Related Issue

#66

Changes Made

-Added SectionCode Enum.
-Added _find_section_by_code() function.
-Updated the related functions like _find_problems_section().
-Added and updated tests for a document which doesn't contain template_ids for various sections .

Testing

I have added tests similar to the already existing tests but with a different instance of the cdaAnnotator which contains data from that xml document which doesnt have any template_ids.

Checklist

• I have read the contributing guidelines
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Additional Notes

[jenniferjiangkells]

Looks good to me. Thank you so much for your second contribution @Vortex-21! 🌟

[Vortex-21]

Looks good to me. Thank you so much for your second contribution @Vortex-21! 🌟

@jenniferjiangkells Thank you so much for your kind words! 😊 I'm really glad I could contribute .