Allow for custom crash directory and FileProtectionType

[melekr]

Usage sample:

    `
    let customDir = try? FileManager.default.url(for: .libraryDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    let directoryUrl = customDir!.appendingPathComponent("my-crash-directory")
    
    let backtraceConfigurations = BacktraceClientConfiguration(credentials: backtraceCredentials,
                                                               dbSettings: backtraceDatabaseSettings,
                                                               reportsPerMin: 10,
                                                               allowsAttachingDebugger: true,
                                                               detectOOM: true,
                                                               crashDirectory: directoryUrl,
                                                               fileProtection: .none)
    
    BacktraceClient.shared = try? BacktraceClient(configuration: backtraceConfigurations)
    `

ref: BT-5555

[melekr]

#157