Renaming of trackers and their merging with libraries

**The Renaming**
The term _tracker_ may be replaced by _worries_ in the scanner page. This is because we're going beyond just recognising trackers as it is our intention to make App Manager's scanner feature as much _informative_ as possible. The motivation behind such a scheme is that App Manager's philosophy revolves around making its users enthusiastic about what their apps are capable of — implicitly or explicitly.

A typical anti-virus (AV) app (or even Google's so-called AI-powered scanner) frequently fails to classify new malware as the malware developers are usually more clever and more dynamic. It is my firm belief that displaying a simple yes/no answer for a malware is not an answer because these _blackbox_ AV software are only good at detecting known malware and that even the most unknowledgeable person is capable of some reasoning regarding whether an app might be good or bad for them. In creating App Manager, it is my intention to spread awareness _implicitly_ so that the user do not actively recognise the changes in them that the app is bringing about, and two years after its first launch, I can finally see _some_ successes in various threads.

In other pages, however, _trackers_ may be renamed to _concerns_. But the renaming is not yet _final_ and if you have a better idea on the naming, feel free to suggest here.

**The Merger**
Trackers and libraries are very interrelated, and maintaining them separately was never a good idea. After much discussion in #599, I have decided to merge them into a single feature in the scanner page.

In order to do this, I shall be maintaining [a separate repository](https://github.com/MuntashirAkon/android-libraries) for holding the trackers and libraries. The benefit of such a repository is that it becomes easier not only for App Manager but also for other project to use what is currently exclusively available to App Manager. This also makes it easier to control the list of trackers and libraries that App Manager use instead of directly relying on third-party services such as Exodus, whose ideals, occasionally, does not align with ours. However, one of the major benefits of this scheme is the user's ability to adhere to a certain threat model instead of App Manager's default threat model, that is, the user will be able to select which [Anti-features](https://f-droid.org/en/docs/Anti-Features/) they would consider as _worries_. By default, we shall consider _advertisements_, _tracking_ and _known vulnerabilities_.