Introduce app_data_file_type attribute.

This gives us an easy way for the policy to refer to all existing or
future types used for app private data files in type= assignments in
seapp_contexts.

Apply the label to all the existing types, then refactor rules to use
the new attribute.

This is intended as a pure refactoring, except that:
- Some neverallow rules are extended to cover types they previous
omitted;
- We allow iorap_inode2filename limited access to shell_data_file and
  nfc_data_file;
- We allow zygote limited access to system_app_data_file.

Also extend check_seapp to check that all types specified in
seapp_contexts files have the attribute, to ensure that the neverallow
rules apply to them. As a small bonus, also verify that domain and
type values are actually types not attributes.

Test: Presubmits
Test: Manual: specify an invalid type, build breaks.
Bug: 171795911
Change-Id: Iab6018af449dab3b407824e635dc62e3d81e07c9
12 files changed