rewrite vsv in Rust for v2

[bahamas10]

This has been a long-time coming on my end, but this is the base for rewriting vsv in rust. First things first:

I know the convenience of having all of vsv in a single bash script that can easily be installed via curl or wget - so i will continue to support that in ./old/vsv.

However, the speed increase when listing services on low-end devices (namely my raspberry pi 2) is amazing. The Rust version is able to grab the information in parallel and process it much faster.

Bash version:

bash-5.1# time /home/dave/dev/vsv/old/vsv status >/dev/null

real	0m0.715s
user	0m0.386s
sys	0m0.301s

Rust version:

bash-5.1# time /home/dave/dev/vsv/target/release/vsv status >/dev/null

real	0m0.014s
user	0m0.000s
sys	0m0.020s

Both processing 14 services.

---

Using a synthetic benchmark with 1,000 services the performance benefit becomes clear:

Bash version

$ time SVDIR=$PWD/benchmarks/service PROC_DIR=$PWD/benchmarks/proc ./old/vsv status >/dev/null

real	0m9.394s
user	0m2.557s
sys	0m5.699s

Rust version

$ time SVDIR=$PWD/benchmarks/service PROC_DIR=$PWD/benchmarks/proc ./target/release/vsv status >/dev/null

real	0m0.057s
user	0m0.016s
sys	0m0.272s