symlinked pump names don't work as expected

Nobody has claimed this yet.

@andreleblanc11 noticed this.

When the pump name directory is a symlink, sr3_tools uses the *link target* as the pump name.

e.g.:

```
sr3-config/
├── _dsh_config
├── cluster_A -> cluster_1/
└── cluster_1

# we're in the cluster_A pump directory, but sr3_tools uses cluster_1 as the pump name
user@srv:~/sr3-config/cluster_A$ sr3l pwd
Data Pump Name: cluster_1. DSH Machine List: /home/user/sr3-config/_dsh_config/cluster_1.list
```

This is a good thing if you want `cluster_A` to just be an alternative name for `cluster_1`.

But it's bad if you want `cluster_A` and `cluster_1` to be different clusters that share the same configs.

The problem comes from this line in the code:

https://github.com/MetPX/sr3_tools/blob/d17a0804f794e97e6844a9476169bf696d8c28aa/bin/sr3_utils#L14

`git rev-parse --show-toplevel` **always** returns a real path and when I wrote it, I wanted to ensure it would work on a system that used symlinked home directories so I used `pwd -P`.

Start at bin/sr3_utils around line 14 and reproduce the issue with a symlinked pump directory, using `sr3l pwd` from the issue example. Trace how `git rev-parse --show-toplevel` and `pwd -P` determine the pump name, then verify that symlinked pump names remain distinct while existing symlinked home-directory behavior is preserved.

Written by the indexing model from the issue text.