Add helper to modify spi raw file, to make experimenting with it easier.
```sh
$ ./littlefs-do --help
Usage: ./littlefs-do <command> [options]
Commands:
-h, --help show this help message for the selected command and exit
-v, --verbose print status messages to the console
stat show information of specified file or directory
ls list available files in 'spiNorFlash.raw' file
mkdir create directory
rmdir remove directory
rm remove directory or file
cp copy files into or out of flash file
settings list settings from 'settings.h'
```
In the process restructure the CMake file for less duplicate
includes/defines for both executables (`infinisim` and `littlefs-do`).
Upload the `littlefs-do` binary built by the CI additionally to the `infinisim` binary.
Use the updated upload-artifact@v3 template to do that.
Press key `I` (shift+`i`) to start a screen capture creating a gif with
the captured screen. Hit `I` again to stop the screen recording.
---
Add gif-h helper header only library
Copied from https://github.com/charlietangora/gif-h3d2657b9ad
Since https://github.com/InfiniTimeOrg/InfiniTime/pull/1097 the fonts
are generated. Support this new way of using fonts.
When InfiniTime isn't a subdirectory of InfiniSim we need to provide
the binary dir when using `add_subdirectory()`. Use `fonts`.
Update README with instructions to install `lv_font_conv`.
The lv_drivers provided monitor driver supports a `MONITOR_ZOOM`-factor
which scales the window by the set factor. This is 'useful when
simulating small screens'.
The zoom can be set as cmake configuration setting `-DMONITOR_ZOOM=1`.
Probably even more usefull for high-dpi screens where 240 pixels is
really tiny.
When pressing `i` create a screenshot of the current InfiniTime screen
by dumping it to a timestamped png or bmp file like
`InfiniSim_2022-03-08_203421.png`.
Add a new configure option `WITH_PNG` with default `ON`. When switched
to `OFF` the screenshots will be created in `bmp` format.
Fixes: https://github.com/InfiniTimeOrg/InfiniSim/issues/5
