Add setting to move synthetic sections

[fuzyll]

What is the feature you'd like to have?
Sometimes, the synthetic sections for builtins wind up in a real segment that breaks things. Users should be able to move it, or otherwise affect where it'll be placed.

Is your feature request related to a problem?
This has come up a few times and I'm not sure if we have a binary or an existing issue for it. I couldn't find either when I searched, and the customer that reported this can't share a binary, so I don't have one. But, it's a problem.

Are any alternative solutions acceptable?
We implemented loader.syntheticSectionBase to deal with this exact problem in shared and kernel caches. But, the setting is marked readOnly. Users can observe, but can't set, the setting in Open With Options.

If this is safe to remove readOnly from, that would be the most straightforward way to do it probably? But, if there were a way for it to be possible to change after loading, that would also be very nice (in the event that you don't realize they'll be in the way until after you've done a considerable amount of work).

Additional Information:
You can probably work around this by creating a custom BinaryView that provides a different default. Here's how we do it in the shared cache stuff: https://github.com/Vector35/binaryninja-api/blob/dev/view/sharedcache/core/SharedCacheView.cpp#L153-L154

[fuzyll]

After discussion with @bdash, we determined it should be safe to remove the readOnly from the setting. As a result, users should be able to move the synthetic sections by using Open With Options or otherwise providing the setting on initial load via the API.

This should be available in builds >= 5.4.10198-dev.

We do not have a solution for changing this after-the-fact at this time. If this is desired in the future, please make a new issue.