Squashed 'external/devlib/' changes from c60737c78..7276097d4

7276097d4 target: Make default modules list empty
6939e5660 target: Cleanup and lazily initialize modules
ce02f8695 Add missing import
b5f311fef tools/docker: Add Docker image support for devlib
233f76d03 test_target.py: Allow specifying connection timeout for Android targets
ac4f581f4 target: tests: Add support for testing ChromeOS targets
c6bd736c8 target: Address pylint issues in ChromeOsTarget class
28b30649f utils/ssh: Fix atexit.register() SshConnection leak
5817866ad Fixed issue where non-consecutive list resulted in incorrect ranges
8247ac91e Add option not to validate PMU counters.
228baeb31 target: Implement target runner classes
1431bebd8 tools/buildroot: Add support for generating Linux target system images
dd84dc7e3 tests/test_target: Test more targets
295f1269e target: Introduce make_temp() for creating temp file/folder on target
84c0935fb utils/ssh: Try to free up resources during client creation
598c0c1d3 tools/android: Add support for creating Android virtual devices
a1718c370 tests/test_target: Read target connection settings from a YAML file
b5715b656 utils/misc: Move load_struct_from_yaml() from WA to devlib
39dfa7ef7 utils/android: Add debug log about connection settings
a83fe5238 test_target: Add copyright statement
613b4fabb ChromeOsTarget: Fix building SSH connection parameter list
be7e73db1 utils/ssh: Load host keys only if strict_host_check is true
e334f8816 target: Customize as_root parameter of *write_value()
38d8053f2 devlib: Remove unused imports
7ccdea6b8 devlib/init: Resolve pylint issues
cb36347df doc/connection: Fix typo Telenet

git-subtree-dir: external/devlib
git-subtree-split: 7276097d4e12ff2b3cfa1bb0ba40cee24ae3372b