Improve PR conflict handling to show conflict line markers where possible

As part of the 7.0 release, Bitbucket removed the ability to look at conflict markers in lines. Work was done to create file level conflict marking to be able to flag files that have conflicts.

File level marking however do not address the following scenarios:

1. As a reviewer, I want to know the content of the conflict because I care about whether the conflict affects other parts of the review
2. As an author, I want to know the content of the conflict because it may influence my work (this could be both code work or talking to someone about their change)
3. As an author, I want to know the content of the conflict because I care about how difficult it is for me to resolve (time management etc)

Suggest more work be done in a similar line to allow the viewing of "simple" conflicts and conflict markers per line where possible, without the need to bring back old 3 way diff functionality or performance issues.