weldr-client has replaced composer-cli so remove all of the code and
tests, adjust various things so they don't expect it to be available,
and rename some things like test/composertest.py to reflect its
exclusive use by lorax.
Python will eventually close open files, but it is recommended to
explicitly close them instead of waiting for the gc or program exit.
This fixes all the uses of open...read/write in the codebase, mostly in
tests.
Make sure that dotfiles are installed when not directly under /
Make sure / is not packaged in the rpm (it will cause a conflict with
the filesystem package).
Make sure that using destination="/" works
This adds empty __init__.py to tests so that a lib.py library of helper
functions can be imported from the tests.
Add captured_output to use with composer-cli tests to capture stdout/err
output from the functions.
(cherry picked from commit eeae331ba0)
