This commit adds a deprecation notice for the `xtools` toolchain
variant, which was deprecated in the commit
a9d85ae472.
Signed-off-by: Stephanos Ioannidis <stephanos.ioannidis@nordicsemi.no>
This commit adds individual documentation page for each toolchain type
based on the content from the `3rd_party_x_compilers.rst` file in order
to improve visibility.
Signed-off-by: Stephanos Ioannidis <root@stephanos.io>