Add Intent Intercept like features

[Intent Intercept](https://github.com/k3b/intent-intercept) allows user to edit the content of intercepted intent before resending it to the destination apps. This is useful not only for debugging purpose but also for other purposes.

## Roadmap
Unlike the original app, my intention is to make it as smooth as possible. This includes all the features of Intent Intercept along with the following extras:
1. [ ] Save mime-specific default apps (via an always button)
2. [x] Add/remove extras (only for known classes)
3. [x] Add/remove flags
4. [x] Add/remove categories
5. [x] Set identifier
6. [x] Set component name
7. [x] Set package name
5. [x] Extended support for exported activities in the activities tab
6. [ ] Save/import/export intents
7. [x] For root users, open non-exported activities via root (for activities tab)
8. [x] Set data and type
9. [ ] Support for receivers and services