Bug description
When uploading a new file into DefectDojo (Engagement, Test, Finding), the title is unique due to the model declaration:
title = models.CharField(max_length=100, unique=True)

Thus, it is not only unique for that Engagement, Test or Finding but for the whole DefectDojo instance.

Steps to reproduce
Steps to reproduce the behavior:

1. Go to Manage Files in Engagement, Test or Finding
2. Upload a first file called "Test"
3. Go to a different Engagement, Test or Finding
4. Upload a new file called "Test"
5. "File with this name already exists" pops

Expected behavior
Even if the Title could be a way of recognizing the file, as DD is intended to store a lot of Findings (then lot of engagements, tests, etc.), it's quite common that the chosen title will often or always match one already existing. For example, naming XSS, or Screenshot 1, etc. Thus, it become more and more complicated with time to find a title that has not been used yet and feature seems impossible to use.

Title should allow non unique values and maybe should allow 1000 chars and not just 100. Or, maybe should be split into 2 fields adding some kind of description in the FileUpload class?