Now that the lint engine can be extended, it becomes possible to run the
lint workflow mutliple times with a different configuration in order to
have some linters run in the desired order.
To do so the lint engine is changed between each workflow run, and a
separated configuration is read which contains the linters for the run.
This diffs introduce a new configuration file, .runlast.arclint. The
linters to be run last (sequentially after the other linters) are moved
from the .arclint configuration file to this one, currently
clang-format and autopep8. These linters are autofix linters which
apply to the whole file, thus leading to a 100% conflict rate with other
Calling arc lint is now equivalent to runnint it twice, the first time
with all the linters excepted clang-format and autopep8, the second
time only with clang-format and autopep8.
The call to arc diff is also modified to match the arc lint
Depends on D3298