Oscilloscope: Add new feature for Triggering

[AsCress]

This is for the addition of the following proposed feature:-

Triggering Controls:

• Currently, the oscilloscope supports only a single type of edge – triggering.
• All three-types of edge triggering: Rising-edge, Falling-edge and Dual-edge can be added.

Actual Behaviour
Currently, we only support hardware based triggering, i.e., using the trigger controls built in the PSLab device. This also has limitations as certain channels support only a single kind of triggering.

Expected Behaviour
Triggering is a feature which we can implement at a software level in the Android app. This would ensure that all kinds of triggering controls are available for all the channels.

Steps to reproduce it
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LogCat for the issue
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Screenshots of the issue
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Would you like to work on the issue?
Yes