feat(search): Faceted search based on mod host (curse/modrinth) (#48)

This also adds a commandline argument library (gumdrop) for dealing
with indices - reseting, reconfiguring, and skipping them. I don't
know which library is best for this case, but gumdrop has shorter
compile times and many fewer dependencies than clap, which is why
I chose it.

Cargo.lock

@@ -903,6 +903,26 @@ version = "0.21.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bcc8e0c9bce37868955864dbecd2b1ab2bdf967e6f28066d65aaac620444b65c"
 
+[[package]]
+name = "gumdrop"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "46571f5d540478cf70d2a42dd0d6d8e9f4b9cc7531544b93311e657b86568a0b"
+dependencies = [
+ "gumdrop_derive",
+]
+
+[[package]]
+name = "gumdrop_derive"
+version = "0.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "915ef07c710d84733522461de2a734d4d62a3fd39a4d4f404c2f385ef8618d05"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
 [[package]]
 name = "h2"
 version = "0.2.5"
@@ -1137,6 +1157,7 @@ dependencies = [
  "env_logger",
  "futures",
  "futures-timer",
+ "gumdrop",
  "log",
  "meilisearch-sdk",
  "rand",