Remove legacy __init__.py code

[mgkwill]

There are multiple places across lava and lava libs codebase that include explicate Namespace packages.

Such as:

lava/src/lava/__init__.py

Line 1 in cfcd72a

__import__("pkg_resources").declare_namespace(__name__)

and:

lava/src/lava/magma/__init__.py

Line 1 in cfcd72a

__import__("pkg_resources").declare_namespace(__name__)

and:
https://github.com/lava-nc/lava-optimization/blob/f7fce219b2b2978d210d9b5ffb5a8168967bf511/src/lava/__init__.py#L4-L8

However since python 3.3 Namespaces are defined implicitly:
PEP 420 -- Implicit Namespace Packages

This issue involves

• Remove all legacy init.py code as defined in PEP 420
• Test the resulting Namespace and Package function
• If Namespace and Packages still function, open pull requests to remove legacy code

[awintel]

Yes, I think this was initially done intentionally by @srrisbud because removing all legacy init.py files is a bad thing. Removing the init.py gives you implicit names spaces but you also have no more chance to write a custom init.py to e.g. simplify imports.
Perhaps there is another way that I'm not aware of.