Update kernel version string to 10.4.1

Update kernel pointer

LTS-development-snapshot-202007.00

LTS-development-snapshot-202002.00

LTS development changes have Source, Demo, and dependencies added for FreeRTOS-IoT-Libraries. These libraries are using FreeRTOS kernel, FreeRTOS-Plus-TCP, and FreeRTOS-Plus-Trace of V10.3.0 tag. FreeRTOS_Plus_TCP and FreeRTOS_Plus_Trace are as used as is, but a few changes are made to FreeRTOS as listed below.

    Removed FreeRTOS/Demo.
    Updated FreeRTOS/readme.txt to remove mentions about the demos.
    Removed FreeRTOS/links_to_doc_pages_for_the_demo_projects.url file as there are no demos present.

A preliminary .gitignore file, to prevent us checking in files unnece…

…ssary. (FreeRTOS#18)

https://github.com/github/gitignore.