OptionConfiguration - customize options via code

[limbonaut]

Allow customizing options via code. One complication is that editing options with sentry-native is only possible before initialization, which might require delaying initialization since the GDScript module isn't available until later. Currently, we don't initialize early (see #39), but eventually, this will become a problem to solve.

References:

• feat: Add OptionConfiguration to replace Runtime/BuildTime  sentry-unity#1888
• Simplify BuildTime and Runtime Options sentry-unity#1621