Add .git-blame-ignore-revs and some instructions for clang-format

7 jobs for clang_format_try_ci in 3 minutes and 58 seconds (queued for 3 seconds)
Status Job ID Name Coverage
  Build
passed #3235769
build

00:03:57

passed #3235774
build_android

00:00:42

passed #3235770
build_clang_libcpp

00:02:53

passed #3235773
build_clazy

00:03:32

passed #3235772
build_mingw64_fedora

00:02:10

passed #3235771
build_ubuntu_16_04

00:02:19

passed #3235768
clang_format

00:01:08