Added file open helper which fixes opening files with too strict FileShare configuration

[devedse]

This PR will solve issues where FileFlows is opening files for a specific purpose but blocking other applications to continue writing.

For example:

File.OpenRead()
Calls:
        public static FileStream OpenRead(string path)
            => new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.Read);

This sets FileShare to .Read this locks the file for all other applications trying to write to it. Thus causing permission issues when for example doing a copy.

CLA

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