[PR #6131/abcba9db backport][stable-6] Interfaces file spaces fix (#6169)

Interfaces file spaces fix (#6131)

* interfaces_file: added test case for #6120

* interfaces_file: reverted code to #fafabed

* interfaces_file: added changelog fragment

* interfaces_file: added missing licenses

* interfaces_file: improved test coverage

* interfaces_file: fixed retrieving option values

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update tests/unit/plugins/modules/interfaces_file/test_interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update plugins/modules/interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* Update tests/unit/plugins/modules/interfaces_file/test_interfaces_file.py

Co-authored-by: Felix Fontein <felix@fontein.de>

* interfaces_file: spacing fix

---------

Co-authored-by: Felix Fontein <felix@fontein.de>
(cherry picked from commit abcba9dbbe)

Co-authored-by: Roman Belyakovsky <roman.beliakovskii@smartly.io>

changelogs/fragments/6131-fix-interfaces_file-for-no-leading-spaces.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - interfaces_file - fix reading options in lines not starting with a space (https://github.com/ansible-collections/community.general/issues/6120).