AAPT2: Adds config support for manipulating resources

aapt2 optimise command can now take a resources config file as an
argument. The config has the name of each resource and a list of
directives. Currently implemented is the "remove" directive which marks
the resource for deletion.

The obfuscation whitelist code and argument name was changed to prevent
confusion.

Test: make aapt2_tests
Bug: b/27523794

Change-Id: I2d8e1985e5ea2286131c25231e2c411f3d9610ce