python: Move the components lib to be compiled in the binary

There has been some debate on how best to distribute the components
library. This change builds the components library into the gem5 binary.
The components library will now function similar to the `m5` library.
There is no need for awkward imports or obtaining the library from some
third-party source.

Additional incorporated in this patch:
* Added `__init__.py` to the Python modules.
* Fixed a typo in the `abstract_ruby_cache_hierarchy.py` filename.
* Ensured that imports within the library are relative.

Issue-on: https://gem5.atlassian.net/browse/GEM5-1023
Change-Id: I3988c8710cda8dcf7b21109a2cf5c3f1608cc71a
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/49690
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Austin Harris <mail@austin-harris.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
88 files changed