This modifies the CPU interface to more accurately match an
AArch64-supporting CPU as opposed to an ARM11 one. Two of the methods
don't even make sense to keep around for this interface, as Adv Simd is
used, rather than the VFP in the primary execution state. This is
essentially a modernization change that should have occurred from the
get-go.

* GDBStub works with both Unicorn and Dynarmic now

* Tidy up

Rather than having to type out the full std::map type signature, we can
just use a straightforward alias. While we're at it, rename
GetBreakpointList to GetBreakpointMap, which makes the name more
accurate. We can also get rid of unnecessary u64 static_casts, since
VAddr is an alias for a u64.

Keeps everything under the same namespace. While we're at it, enclose
them all within an inner anonymous namespace.

In all cases, a virtual address is being passed in, not a physical one.

General moving to keep kernel object types separate from the direct
kernel code. Also essentially a preliminary cleanup before eliminating
global kernel state in the kernel code.

Ensures both operands in comparisons are the same signedness.

* More improvements to GDBStub
- Debugging of threads should work correctly with source and assembly level stepping and modifying registers and memory, meaning threads and callstacks are fully clickable in VS.
- List of modules is available to the client, with assumption that .nro and .nso are backed up by an .elf with symbols, while deconstructed ROMs keep N names.
- Initial support for floating point registers.

* Tidy up as requested in PR feedback

* Tidy up as requested in PR feedback

* GDB Stub should work now.

* Applied clang-format.

* Replaced htonll with swap64.

* Tidy up.

This gets gdbstub working at least to the point where clients can
communicate with it.

What works:
- Reading/writing GPRegs
- Reading/writing memory
- Interrupting the emulated program and continuing

What does NOT work:
- Breakpoints. Sizes have been updated to u64, but support will need to be
  added in the interpreter for them to work.
- VRegs. Mostly because my gdb was having issues with 128-bit regs for
  some reason. However, the current u128 representation is a bit
  awkward to use and should probably be updated first.

* Fixes some cast warnings, partially fixes citra #3064

* Converted casts to uint32_t to u32

* Ran clang-format

Core::System().GetInstance().IsPoweredOn() -> Core::System::GetInstance().IsPoweredOn()

Corrects a few issues with regards to Doxygen documentation, for example:

- Incorrect parameter referencing.
- Missing @param tags.
- Typos in @param tags.

and a few minor other issues.

Also uses size_t as the length indicator type, as is common with buffers.

Currently, this is only ever queried, so adding a function to check if the
server is enabled is more sensible.

If directly modifying this externally is ever desirable, it should be done
by adding a function to the interface, rather than exposing implementation
details directly.