Improve GCP wodle options descriptions

[GGP1]

Description

Closes #5699.

Improves the GCP wodle gcp-bucket and gcp-pubsub configuration options descriptions.

Checks

Docs building

• Compiles without warnings.

build

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reading sources... [100%] user-manual/reference/ossec-conf/gcp-bucket                                      	 
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The HTML pages are in home/python/build/html.
[sphinx-autobuild] Serving on http://0.0.0.0:8000/
[I 231002 19:40:31 handlers:92] Reload 1 waiters: /home/python/docs/user-manual/reference/ossec-conf/gcp-bucket.rst
[I 231002 19:40:31 handlers:135] Browser Connected: http://0.0.0.0:8000/user-manual/reference/ossec-conf/gcp-bucket.html

Code formatting and web optimization

• Uses three spaces indentation.
• Adds or updates meta descriptions accordingly.
• Updates the redirects.js script if necessary (check this guide).

Writing style

• Uses present tense, active voice, and semi-formal registry.
• Uses short, simple sentences.
• Uses bold for user interface elements, italics for key terms or emphasis, and code font for Bash commands, file names, REST paths, and code.

[fdalmaup]

We could add tables like the ones that the aws-s3 module has to summarize the available options and if they are mandatory or not (e.g. the one for the bucket's options).

Also, we should check if these changes will be part of release 4.6.0 or not.

[fdalmaup]

The changes are correct, but the format should be modified to have the different bucket options in a hierarchy level lower than the Bucket options title, thus also removing the bucket\ prefix for each option.

[fdalmaup]

LGTM!

[javimed]

@GGP1 what if we made changes to get the result in the image below? Look into the content and the right sidebar as well. You'll see further changes in structure and an additional table for the attributes and the clarification ... (attribute) in the type entry title. Please let me know what you and team think of these suggestions which I can commit, modify, or even drop. Thank you.

[GGP1]

@javimed that looks better in my opinion. Feel free to commit the changes you consider necessary.

[javimed]

Ok, I added a few changes. Let me know if it's ok and if we're good to merge this PR, @Selutario @fdalmaup