Revert fixing codacy complaints via "setup.cfg"

This reverts commit 20a155a[^0], because `prospector` doesn't pick up
`pep257` options from "setup.cfg", so these options don't actually fix
the complaints. This means that, until [prospector-dev/prospector#376][0] is
implemented, or until `prospector` implements gathering tool
configuration from "setup.cfg", we have to put yet another dotfile into
the project root, if we want fine grained control over the applied
checks.
Since we have to do this anyway, this commit not only removes the
section from "setup.cfg", but also puts the equivalent configuration
into the new ".prospector.yaml". While at it, I took the liberty of also
starting to configure paths which should be ignored by `prospector`,
because that one line really doesn't have to be in its own commit.

[0]: prospector-dev/prospector#376
[^0]: 20a155a

.prospector.yaml

@@ -0,0 +1,3 @@
+ignore-paths: ["ci"]
+pep257:
+  disable: ["210", "212", "213"]

setup.cfg

@@ -99,6 +99,3 @@ coverage_flags =
     nocov: false
 environment_variables =
     -
-
-[pydocstyle]
-ignore = 210, 212, 213