1. separate rom include files and linkscript to esp_rom
2. modefiy "include rom/xxx.h" to "include esp32/rom/xxx.h"
3. Forward compatible
4. update mqtt
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
