Replace the PdfWriter method add_js with add_action

[j-t-1]

Once a new Action class is implemented, change the method add_js(self, javascript: str) to add_action(self, action: Action).

Use a DeprecationWarning with replacement.

[stefan6419846]

Please avoid creating issues without the templates wherever possible. In this case, using the feature template should have been possible.

[j-t-1]

#3552 is currently a dependency on this, as this issue relies on the new Actions class.

@stefan6419846 What do you think of closing that PR, implement this, and then re-implement the page level add_action?

[stefan6419846]

Why not simply finishing this PR and then tackle this? This PR awaits you implementing the request changes and requesting a review once you think this is ready for review again.

[j-t-1]

Why not simply finishing this PR and then tackle this? This PR awaits you implementing the request changes and requesting a review once you think this is ready for review again.

I use add_js and so would be useful to get the change, and it could be quicker than the existing PR. I have done some more changes for the existing PR and is ready for review.

[stefan6419846]

existing PR and is ready for review

Then please use the proper "Request review" button from the PR, as requested by the contribution guide to improve the overview from my side.