oeqa/core: Add loader, context and decorator modules
loader: Implements OETestLoader handling OETestDecorator
and filtering support when load tests. The OETestLoader is
responsible to set custom methods, attrs of the OEQA
frameowork.
[YOCTO #10231]
[YOCTO #10317]
[YOCTO #10353]
decorator: Add base class OETestDecorator to provide a common
way to define decorators to be used over OETestCase's, every
decorator has a method to be called when loading tests and
before test execution starts. Special decorators could be
implemented for filter tests on loading phase.
context: Provides HIGH level API for loadTests and runTests
of certain test component (i.e. runtime, sdk, selftest).
