Add DELETE operation in SFTPOperator

[Dawnpool]

This PR adds DELETE operation in SFTPOperator, related to the issue(#40365) I have raised before.

Currently, SFTPOperator only supports PUT and GET operations. With this update, you can now delete files or directories on a remote SFTP server by putting paths in the remote_filepath parameter.

NOTE: The local_filepath parameter does nothing in DELETE operation even if it's provided

closes: #40365

[eladkal]

NOTE: The local_filepath parameter does nothing in DELETE operation even if it's provided

Then you need to identify this case in the code and raise exception. It's best to tell users what is not right rather then ask them to read documentation.

example:

airflow/airflow/sensors/base.py

Lines 159 to 160 in 5ff07fa

	if soft_fail is True and never_fail is True:
	raise ValueError("soft_fail and never_fail are mutually exclusive, you can not provide both.")

(Don't forget to add test case to cover this case)

Alternatively, if preferred, you can just log that local_filepath was ignored (with some informative message).

[Dawnpool]

Thanks for your review @eladkal
Just added an exception raise and test code for it. Please let me know if you have any more concerns.

[Dawnpool]

Thanks for your review @morooshka
I've made changes based on your feedback in this commit.
Feel free to let me know if you have any more feedback :)

[potiuk]

Looks cool. Thanks @morooshka for all the valuable comments !