Add "Autosave RAW" setting to sub-ghz app.

[CodyTolene]

Not sure if we should make this a part of unleashed, or the main firmware? Or at all? I'm not even sure if this is even a good idea yet but wanted to get this PR out to get an opinion on it as I tinker with it. Feel free to share thoughts, thanks all.

Edit: Side note, I'm also interested in maybe combining with the below work was well. Maybe as a new app?

flipperdevices/flipperzero-firmware#1667

What's new

• Autosave sub-ghz RAW data. Intention: bypass 55 capture/heap size max limits.

Verification

• In "Sub-GHz" application read & capture RAW, see autosave function.

Todo

• Add new "Autosave RAW" setting.
• Autosave captures when setting is "On".
• Default functionality when setting is "Off".

Checklist (For Reviewer)

• PR has description of feature/bug
• Description contains actions to verify feature/bugfix
• I've built this code, uploaded it to the device and verified feature/bugfix

[CodyTolene]

Temporary for testing. Todo: Revert.

[xMasterX]

Hi, please make it as separate external app, not in main subghz app for now, you can copy subghz app since its already prepared to be external / or make subghz external in this PR
we have discussed this feature multiple times with our team, and found that it can't be done without affecting performance of receiver, but since you already started work on it, if you want to continue make it as second external app, if all goes well this will be merged into main app,
or just make subghz external again so you will see how much ram we have in result
subghz currently moved into internal since we have not enough ram for signals
but if you could make something like "swap file" in regular os, but for subghz in flipper firmware, it will solve that issue