Fix FilesystemMixin APIs for file modifications

[tcaiazzi]

Description:
The current implementation of the FilesystemMixin APIs includes calls to the strip() method, which inadvertently disrupts the formatting of modified files.

To address this issue, we need to replace the following strip() method calls:

Kathara/src/Kathara/foundation/model/FilesystemMixin.py

Line 210 in 56ba82a

new_lines.append(line.strip())

Kathara/src/Kathara/foundation/model/FilesystemMixin.py

Line 245 in 56ba82a

new_lines.append(line.strip())

Kathara/src/Kathara/foundation/model/FilesystemMixin.py

Line 287 in 56ba82a

new_lines.append(line.strip())

with .replace("\n\r", "\n").replace("\r\n", "\n") to handle new line chars.

This modification will ensure that the formatting of modified files remains intact when using the FilesystemMixin APIs.