* kconfig: Fix invalid dependancy in fsdrv
LV_USE_FS_* symbols are integers, instead of usual booleans.
We must treat them as such.
* ci: Get LVGL version from git tag
* docu: Update Espressif readme
* ci run apt update before installing
Simplified workflow and documentation, by moving the
development package prerequisites into a new build script
`scripts/install-prerequisites.sh`.
Also, moved prerequisite installation into its own CI step and
removed explicit working directory change as it is no longer
needed (`main.py` does it).
