Refactor FTP client into a component library

[dvosully]

I have refactored the FTP client into a component library which can be included as a component of a larger project. This removes the need to copy the key files into a personal project, providing a clear separation between library and application, and making back-porting changes much more straightforward. Instead, the whole repository can be included as a submodule in an external project.

The demo application can still be built as a standalone project, and it is otherwise unchanged. To build the demo app now, cd to ./esp-idf-ftpClient/test and then configure and build the application as normal.

To use the component in a larger project (myproject):

• create a 'components' directory in the 'myproject' directory.
• clone the esp-idf-ftpClient component into the 'components' directory eg. git submodule add https://github/nopnop2002/esp-idf-ftpClient.git
• Edit 'myproject\main\CMakeLists.txt' and add "esp-idf-ftpClient" to the 'REQUIRES' section (see esp-idf-ftpClient\test\main\CMakeLists.txt for an example)

[nopnop2002]

Changed to component.

Edit 'myproject\main\CMakeLists.txt' and add "esp-idf-ftpClient" to the 'REQUIRES' section

No changes needed. Simply copy the component to your project.

[dvosully]

Thanks for the update. The proposed PR was structured that the entire repo could simply be referenced as a submodule by git, whereas the modifications you made do (as you mentioned) require copying the component directory into your project. It still works, but IMO a bit less clean.

[nopnop2002]

The changes I made were based on the directory structure used in the official ESP-IDF sample. I think Espressif recommends this kind of directory structure.

https://github.com/espressif/esp-idf/tree/master/examples/wifi/antenna https://github.com/espressif/esp-idf/tree/master/examples/ethernet/basic https://github.com/espressif/esp-idf/tree/master/examples/ethernet/enc28j60

./bluetooth/nimble/throughput_app/blecent_throughput/components ./bluetooth/esp_ble_mesh/ble_mesh_coex_test/components ./bluetooth/esp_ble_mesh/aligenie_demo/components ./system/unit_test/components ./system/console/advanced/components ./system/gcov/components ./peripherals/spi_master/hd_eeprom/components ./peripherals/dedicated_gpio/soft_uart/components ./peripherals/dedicated_gpio/soft_i2c/components ./peripherals/dedicated_gpio/soft_spi/components ./storage/custom_flash_driver/components ./build_system/cmake/plugins/components ./build_system/cmake/import_prebuilt/prebuilt/components ./build_system/cmake/import_lib/components