Remove TLS and NET options from config files and scripts.
Note that this fails check-names.sh because options that TLS and NET
files use are no longer present in config.h.
Enable the MBEDTLS_AES_ROM_TABLES option in the
configs/config-no-entropy.h to place AES lookup tables in ROM. This
saves considerable RAM space, a resource that is very limited in small
devices that use this configuration.