Number of e-mails in backlog now limited to reduce UI related loading time lag

Build up of email notifications causes lag of dashboard menus and overall game.

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COLLECTED HARDWARE DATA
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Application version: Beta 4.0-2

Device
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Model: Inspiron 15 7000 Gaming (Dell Inc.)

Operating system: Windows 10 (10.0.0) 64bit

RAM size: 8 GB

Battery status: Charging
Battery level: -1

Processor device
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Type: Intel(R) Core(TM) i5-7300HQ CPU @ 2.50GHz
Core count: 4
Frequency: 2 GHz

Grahpics device
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Vendor: NVIDIA
Type: NVIDIA GeForce GTX 1050 Ti
Memory size: 4 GB

Screen summary
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Full screen: True
Resolution: 1920 x 1080 @ 60Hz