This change to the template action plugin make template use the
platform's native newline_sequence for Jinja.
We also added the option `newline_sequence` to change the newline
sequence using by Jinja if you need to use another newline sequence than
the platform default.
This was previously discussed in
https://github.com/ansible/ansible/issues/16255#issuecomment-278289414
And also relates to issue #21128
Per a change in jinja2 2.9, local variables no longer are prefixed
with l_, so this updates AnsibleJ2Vars to pull in all locals (while
excluding some) regardless of name.
Fixes#20063
(cherry picked from commit 4d49b317929b86e1fc1b0cbace825ff73b372dc7)
