Dynamically loaded module support

[Martmists-GH]

Some games (notably the Mario Party titles) load NROs at runtime. I'd like to see what possibilities there are to hook into these modules, if any.

Some concerns with these modules:

• They may be loaded (and unloaded) at any point
• There is no way for sail to easily link symbols to these modules
• Hooking into the nn::ro::LoadModule method seems to fail(?) Error on my part
• Jumps to loaded modules may not fit in a branch instructions, so multiple-op jumps may be necessary, and these might not always fit in small functions.
• Hakkun uses a wrapper around nn::ro::detail::RoModule which may not work for dynamic loads (especially since the amount loaded at once is unknown)
• possibly more that I forgot about

Rather than a feature request, I'm hoping this issue can be treated as a discussion thread for other problems and possible solutions, in case anyone wants pointers on implementing support and problems they may have to solve.

[fruityloops1]

Some notes:

• Sail index-based modules should be Completely removed for this and replaced with them being looked up by build id
• To make a trampoline hook work past the max branch distance, I would map a page using MapProcessCodeMemory right before/after the hooked module, depending on which side is less far away (and given that neither are also more far away than the branch limit), and store gadgets to call that will call the trampoline callback function using absolute offset (on aarch64 this would have to dirty a specific register, not on ilp32), and this page would ideally act as a pool for all trampolines in that module, which could be a Problem due to having to unmap/modify/remap the page and concurrency issues with that
• RTLD does not provide a callback for when a new manual module is loaded, so there would have to be an API that allows the user to make RoUtil recollect the RoModule objects for dynamic modules
• The lifetime/ownership of the hakkun RoModule class for these modules has to be managed somehow (without allocations)