[`pep8_naming`] Add fixes `N804` and `N805` (#10215)
## Summary
This PR fixes for `invalid-first-argument` rules.
The fixes rename the first argument of methods and class methods to the
valid one. References to this argument are also renamed.
Fixes are skipped when another argument is named as the valid first
argument.
The fix is marked as unsafe due
The functions for the `N804` and `N805` rules are now merged, as they
only differ by the name of the valid first argument.
The rules were moved from the AST iteration to the deferred scopes to be
in the function scope while creating the fix.
## Test Plan
`cargo test`
