Enable Search For MTR & IPG

[AEFeinstein]

Currently the Toolbar search button when viewing the MTR & IPG searches the card database. It should search the visible document instead, like how it's overridden for the Comprehensive Rules.

The first search should jump to the first result on the page. The search text shouldn't be cleared after each search. If the same text is searched multiple times, the next results should be jumped to. If new text is searched, it should start from the top again.

[AEFeinstein]

https://developer.android.com/reference/android/webkit/WebView#findAllAsync(java.lang.String)
https://developer.android.com/reference/android/webkit/WebView#findNext(boolean)
https://developer.android.com/reference/android/webkit/WebView.FindListener.html