Tab completion

Complete app names, build types, operations and ports for build_app.sh and flash_app.sh in Bash.

./scripts/setup_tab_completion.sh       # adds a source line to ~/.bashrc
source ~/.bashrc
./scripts/build_app.sh gp<Tab>          # gpio_test

esp32_completion.sh defines the completion functions and registers them for build_app.sh, ./build_app.sh, scripts/build_app.sh and ./scripts/build_app.sh (and the same for flash_app.sh). It reads the app names and build types from the project's app_config.yml and the ports from /dev. To try it without changing ~/.bashrc, source it in the current shell:

source ./scripts/esp32_completion.sh

tests/test_tab_completion.sh checks the installation and the completions; see Testing and CI.