Refactor RCCL install guide into several pages (#1427)

* Refactor RCCL install guide into several pages

* Changes from code review and new docker guide

* Add missing entries to ToC

* Minor fixes

* Fix help strings

* Edits after review and remove extra white space

install.sh

@@ -41,7 +41,7 @@ function display_help()
     echo "RCCL build & installation helper script"
     echo " Options:"
     echo "       --address-sanitizer     Build with address sanitizer enabled"
-    echo "    -d|--dependencies          Install RCCL depdencencies"
+    echo "    -d|--dependencies          Install RCCL dependencies"
     echo "       --debug                 Build debug library"
     echo "       --enable_backtrace      Build with custom backtrace support"
     echo "       --disable-colltrace     Build without collective trace"
@@ -52,7 +52,7 @@ function display_help()
     echo "    -i|--install               Install RCCL library (see --prefix argument below)"
     echo "    -j|--jobs                  Specify how many parallel compilation jobs to run ($num_parallel_jobs by default)"
     echo "    -l|--local_gpu_only        Only compile for local GPU architecture"
-    echo "       --amdgpu_targets        Only compile for specified GPU architecture(s). For multiple targets, seperate by ';' (builds for all supported GPU architectures by default)"
+    echo "       --amdgpu_targets        Only compile for specified GPU architecture(s). For multiple targets, separate by ';' (builds for all supported GPU architectures by default)"
     echo "       --no_clean              Don't delete files if they already exist"
     echo "       --npkit-enable          Compile with npkit enabled"
     echo "       --openmp-test-enable    Enable OpenMP in rccl unit tests"