Refactor, run clean command after each test, improve logic for setting default targets.

[HakkyuKim]

Sorry for the unexpected huge diff, adding default targets was not as straightforward as I originally thought. I may have done some over refactoring but I already had planned the changes for #230. It was simpler to work with the refactored code so I decided to apply it a bit early.

This PR must be merged after adding the --platforms option in integration_test.yml.

Summary:

• Run clean command after each test to save disk space. (Nothing has changed between line 136~237)
• Don't catch exceptions and print stack trace.
• Fix incorrectly used nested f-string.
• Introduce Target which encapsulates a Tizen device.
• Introduce TargetManager which finds and manages a collection of Targets.
• Update outdated docstrings.
• Define some words used in code, such as target, platform, etc.
• Allow tool to select all connected targets for test devices by default.
• Add --platforms option which takes inputs of the form <device_profile>-<tizen_version>, the tool will find all satisfying targets and serve them as test devices.

# When connected with 4 emulators with different platforms.
./tools/run_command.py test --plugins wakelock
============= TEST RESULT =============
SUCCEEDED: wakelock ('mobile-6.0', 'M-6.0-x86', 'emulator-26131')
SUCCEEDED: wakelock ('wearable-5.5', 'W-5.5-circle-x86', 'emulator-26121')
SUCCEEDED: wakelock ('wearable-4.0', 'w-0521-1', 'emulator-26111')
SUCCEEDED: wakelock ('tv-6.0', 'T-samsung-6.0-x86', 'emulator-26101')
All tests passed!

./tools/run_command.py test --plugins wakelock --platforms wearable-5.5
============= TEST RESULT =============
SUCCEEDED: wakelock ('wearable-5.5', 'W-5.5-circle-x86', 'emulator-26121')
All tests passed!

[bbrto21]

LGTM

[bbrto21]

I can't test with wearable device not emulator.
because, the Tizen version includes the patch number on device.
Can someone test below command on product? I only have a test device with unofficial platform image now.

sdb capability 
platform_version:5.5.0.2

[HakkyuKim]

@bbrto21
I did not realize there were more numbers behind the first dot, I'll fix this.

[HakkyuKim]

@bbrto21 I did not realize there were more numbers behind the first dot, I'll fix this.

Actually, I've set the default target as wearable-5.5 for now and since wearable-5.5.0.2 is technically not the exact version, the error message I've seen offline on your machine is correct.

I thought about improving this, but left it as a TODO.

plugins/tools/commands/integration_test.py

Lines 100 to 102 in 0ca3a10

	if not test_targets:
	# (TODO: HakkyuKim) Improve logic for setting default targets.
	test_targets.append(_DEFAULT_TEST_TARGET)

Since the issue came up, I'll find a better way to set default targets.

[HakkyuKim]

@bbrto21
You should be able to test with any connected targets now.

[bbrto21]

@HakkyuKim
Thank you, it works fine :)