raygun: Define chat directories for attachments

[dariusc93]

In the current implementation, attachments are stored at the root of constellation directory, but may make things a bit more unorganized. What can be done is we can define a conversation directory where each directory is defined by its conversation id and store attachments there instead of the root directory.

Note:

• This will only be for files being attach from disk and not from constellation.
• May require signaling to notify the task of any updates to Directory to properly save/export without a timer (see #374)