Take abseil as a dependency

1. Add abseil-cpp as a submodule. We are tracking the latest LTS
release, which is lts_2024_01_16.
2. Replace glog/gflags with absl::log and absl::flags.
3. Remove miniglog
4. Also take a whack at making the bazel build work with
   abseil-cpp and gtest.

There are a number of TODOs in this CL that still need to be resolved.

Change-Id: I39355ed7d61375be4ebcbc8596d9cc70acc1c678

examples/bicubic_interpolation.cc

@@ -39,9 +39,10 @@
 
 #include <utility>
 
+#include "absl/log/check.h"
+#include "absl/log/initialize.h"
 #include "ceres/ceres.h"
 #include "ceres/cubic_interpolation.h"
-#include "glog/logging.h"
 
 using Grid = ceres::Grid2D<double>;
 using Interpolator = ceres::BiCubicInterpolator<Grid>;
@@ -87,7 +88,7 @@ static double f(const double& x, const double& y) {
 }
 
 int main(int argc, char** argv) {
-  google::InitGoogleLogging(argv[0]);
+  absl::InitializeLog();
   // Problem sizes
   const int kGridRowsHalf = 9;
   const int kGridColsHalf = 11;