* fbt: reduced amount of redundant compilation units
* fbt: added GatherSources() method which can reject source paths starting with "!" in sources list; optimized apps' source lists
* docs: updated on path exclusion for `sources`
* apps: examples: fixed example_advanced_plugins source list
* docs: more details on `sources`; apps: narrower sources lists
* Storage: count opened files
* Storage: sd mount
* Storage: prompt to mount SD card if not mounted
* F18: update API
* F18: update API version
* Fix logger naming scheme
* Storage: storage_files_count -> storage_open_files_count
Co-authored-by: あく <alleteam@gmail.com>