WIP: Parse gitattributes in the Web IDE

What does this MR do?

Parses and uses the encoding options in .gitattributes if it exists. If the file doesn't exist, then the behaviour falls back to the original of relying on the binary key.

If it does exist, it gets parsed & then compares the file name to check if it exists in the .gitattributes, if it does, it uses this encoding.

What are the relevant issue numbers?

Closes #13352 (moved)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides