CI: Add NetBSD target (#180)

* Remove the `sys-info` crate

It offers much more features than we currently use.

Additionally, it was preventing me to cross-compile for NetBSD.

Since we were just using the `hostname()` function from the crate,
I went ahead and stole it.

* Add NetBSD target

* Fix FreeBSD clippy warnings

Cargo.lock

@@ -1839,16 +1839,6 @@ dependencies = [
  "unicode-ident",
 ]
 
-[[package]]
-name = "sys-info"
-version = "0.9.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0b3a0d0aba8bf96a0e1ddfdc352fc53b3df7f39318c71854910c3c4b024ae52c"
-dependencies = [
- "cc",
- "libc",
-]
-
 [[package]]
 name = "tar"
 version = "0.4.38"
@@ -2058,6 +2048,7 @@ dependencies = [
  "glob",
  "home",
  "lazy_static",
+ "libc",
  "nix 0.24.2",
  "notify-rust",
  "parselnk",
@@ -2069,7 +2060,6 @@ dependencies = [
  "shell-words",
  "shellexpand",
  "strum 0.24.1",
- "sys-info",
  "tempfile",
  "thiserror",
  "tokio",