[clang-format][PR45816] Add AlignConsecutiveBitFields

Summary:
The following revision follows D80115 since @MyDeveloperDay and I apparently both had the same idea at the same time, for https://bugs.llvm.org/show_bug.cgi?id=45816 and my efforts on tooling support for AMDVLK, respectively.

This option aligns adjacent bitfield separators across lines, in a manner similar to AlignConsecutiveAssignments and friends.

Example:
```
struct RawFloat {
  uint32_t sign : 1;
  uint32_t exponent : 8;
  uint32_t mantissa : 23;
};
```
would become
```
struct RawFloat {
  uint32_t sign     : 1;
  uint32_t exponent : 8;
  uint32_t mantissa : 23;
};
```

This also handles c++2a style bitfield-initializers with AlignConsecutiveAssignments.
```
struct RawFloat {
  uint32_t sign     : 1  = 0;
  uint32_t exponent : 8  = 127;
  uint32_t mantissa : 23 = 0;
}; // defaults to 1.0f
```

Things this change does not do:
 - Align multiple comma-chained bitfield variables. None of the other
   AlignConsecutive* options seem to implement that either.
 - Detect bitfields that have a width specified with something other
   than a numeric literal (ie, `int a : SOME_MACRO;`). That'd be fairly
   difficult to parse and is rare.

Patch By:  JakeMerdichAMD

Reviewed By: MyDeveloperDay

Subscribers: cfe-commits, MyDeveloperDay

Tags: #clang, #clang-format

Differential Revision: https://reviews.llvm.org/D80176