Make item add and edit safer to use on client-side

[pvj]

• add template, edit template updates include: better representation of episode states and action on the form
• add, edit api: ability to data update w/o files, ability to broadcast update w/o files, extended error handling

Updated HTML templates of add and edit item.
Refactored parts of add and edit api but it should still work with the current schema and data. This is what we have to test.

Important changes and details include;

• Now you can upload au or img files by themselves
• Now you can reset image upload or audio upload on add and edit
• Adding new episode must include a picture too
• If no picture added we try to fall back to the show url or the lahmacun logo
• layout and style updates
• When writing files to disk: Archive to lahmastore is selectable on edit, on by default on add
• Arcsi cleans up tmp files after successful broadcast edit

Please take a look I will be testing this a lot too.

[pvj]

@tuz666 I fixed the code that threw test errors. Thanks for your work, it is reasssuring to have this test suite running and we can easily debug exceptions introduced to any api endpoint.

The PR now should be ready for review. .

[tuz666]

In my PR I totally missed this part where you separated the handling of the form depending on the existence of the attached image and audio files.
This could be a nice potential addition in the future (or maybe we can handle this under your media schema idea)

[pvj]

That's too bad this was the main improvement on this branch.

I think what I would do now in this situation is the following:

• Merge your PR to main
• Rebase my branch on top of the new main (with your changes)

Then we can possibly easily integrate these changes from my branch. What do you think?

[tuz666]

Most of the proposed features were covered in #199

This part was missing and I think it would be nice to implement:

add, edit api: ability to data update w/o files, ability to broadcast update w/o files, extended error handling

[pvj]

@tuz666 This branch is now rebased to latest master. There might be errors caused by the rebasing and conflict resolution. On the other hand now we have only the changes for editing with empty files.