Move (almost all) Travis CI jobs to container-based infrastructure (#2333)

Container-based VMs promise significantly faster boot times.

More or less related changes:
- Added a JOBNAME to all jobs.
- Added `install-noapt` target to several Makefile.travis files to
  avoid `sudo apt-get install ...` steps. Those installations are
  now handled by the apt addon of Travis. The `install` targets are
  kept anyway to keep the makefiles self-contained.
- Removed a legacy workaround from the Coverity Scan job as it
  isn't necessary anymore to fiddle with the cerificates of
  scan.coverity.com.
- Fixed the Mbed and the Zephyr jobs.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu

targets/zephyr/Makefile.travis

@@ -29,17 +29,17 @@ install-apt-get-deps:
 install-zephyr-sdk:
 	wget https://github.com/zephyrproject-rtos/meta-zephyr-sdk/releases/download/0.9.2/zephyr-sdk-0.9.2-setup.run -O ../zephyr-sdk-0.9.2-setup.run
 	sh ../zephyr-sdk-0.9.2-setup.run -- -y -d $(CURDIR)/../zephyr-sdk-0.9.2
-	wget https://cmake.org/files/v3.8/cmake-3.8.2-Linux-x86_64.sh
-	sudo sh cmake-3.8.2-Linux-x86_64.sh --prefix=/usr/local --exclude-subdir
 	cmake --version
 
 # Fetch Zephyr Project repository and install python dependencies.
-install-zephyr: install-apt-get-deps
+install-zephyr:
 	git clone https://github.com/zephyrproject-rtos/zephyr.git ../zephyr -b v1.10.0
+	pip3 install --user -U setuptools
 	pip3 install --user -r ../zephyr/scripts/requirements.txt
 
 # Perform all the necessary (JerryScript-independent) installation steps.
-install: install-zephyr-sdk install-zephyr
+install-noapt: install-zephyr-sdk install-zephyr
+install: install-apt-get-deps install-noapt
 
 
 ## Targets for building Zephyr with JerryScript.