nvs_flash_init may return an error code in some cases, and applications
should check this error code (or at least assert on it being ESP_OK, to
make potential issues more immediately obvious).
This change modifies all the examples which use NVS to check the error
code. Most examples get a simple ESP_ERROR_CHECK assert, while NVS
examples, OTA example, and NVS unit tests get a more verbose check which
may be used in real applications.
rename nvs host test folder, modify .gitlab-ci.yml
remove unit-test-app build
re-format unit test files
remove extra newlines in project.mk
some refactoring for unit test part in project.mk
add build files of unit-test-app in gitignore
add README.md for unit test app
correct headings in README.md
remove files and make minor tweaks in unit test app
update .gitlab-ci.yml to use unit test app
delete unused lines in component_wrapper.mk
delete periph_i2s.h and lcd test
add text floating point in components/esp32/test/Kconfig
correct idf test build paths in .gitlab-ci.yml
