Based on the suggestions mentioned by @TSRBerry in #144.
Speeds up compilation time by using ccache + fallbacks to the latest libnx commit if the build process fails with the libnx build available in the devkitPro image.
Adds the DataTransferTask and DataTransferProgressDisplay classes, which use repurposed logic from the DownloadTask and EtaProgressDisplay classes, respectively. The EtaProgressDisplay class and EtaProgressInfo struct have been removed.
Other changes include:
* DownloadTask: heavily simplified logic by using DataTransferTask as the base class.
* DumpOptionsFrame: implement some additional/experimental changes.
* OptionsTab: update logic to use the new DataTransferProgressDisplay class.
* Use forward declarations for type definitions wherever suitable (e.g. NcaContext, BucketTreeContext).
* Replace references to "DumpDestination" with "OutputStorage".
* Replace references to "append key area" with "prepend key area".
* Update LZ4 to v1.9.4.
* Update Material Icons font to 2022-08-01.
* RootView: change USB-related icons, reflect how many UMS devices are currently connected to the console, provide a way for child views to retrieve the populated UMS devices vector.
* Tasks: implement GetUmsDevices().
* Update borealis.
* Update libusbhsfs.
* Begin implementation of a DumpOptionsFrame class to display configurable options before starting a new dump process.
* bktr: rename bktrIsValidSubstorage() to bktrIsValidSubStorage(), use bktrIsValidSubStorage() in bktrInitializeCompressedStorageContext(), fixed a bug in bktrReadCompressedStorage() where Sparse substorages wouldn't be allowed.
* GamecardTab: push a DumpOptionsFrame object onto the view stack if the XCI option is clicked.
