Enable Python auto-formatting on //net/data and //net/tools

Causes "git cl format" and "git cl upload" presubmit checks to format
changed lines in a review to adhere to our style guide (PEP-8).

Bug: 846432
Change-Id: I9330b3786d3a860bcbe79b5b5299b966ac6bd1c0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1989511
Auto-Submit: Andrew Grieve <agrieve@chromium.org>
Reviewed-by: Paul Jensen <pauljensen@chromium.org>
Commit-Queue: Paul Jensen <pauljensen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#741185}

net/data/.style.yapf

+[style]
+based_on_style = pep8
+
+# New directories should use a .style.yapf that does not include the following:
+column_limit = 80
+indent_width = 2

net/tools/.style.yapf

+[style]
+based_on_style = pep8
+
+# New directories should use a .style.yapf that does not include the following:
+column_limit = 80
+indent_width = 2