Support nested partitions and partitions directly targeting services (#122)

* Do the nested partition thing

* Tidy up touched code

* Add nested partition test project, not fully functional

* Clean up variable names, move path_metadata mutation strictly into snapshot_reconciler

* Remove path_metadata, snapshotting is now pure

* Factor out snapshot metadata storage to fix a missing case

* Pull instance_name out of per_path_metadata, closer to what we need

* Refactor to make metadata make more sense, part one

* All appears to be well

* Cull 'metadata_per_path' in favor of 'instances_per_path'

* Remove SnapshotContext

* InstanceMetadata -> PublicInstanceMetadata in web module

* Build in snapshot testing system for testing... snapshots?

* Remove pretty_assertions to see if it fixes a snapshot comparison bug

* Reintroduce pretty assertions, it's not the cause of inequality

* Fix snapshot tests with custom relative path serializer

server/Cargo.toml

@@ -28,6 +28,9 @@ log = "0.4"
 maplit = "1.0.1"
 notify = "4.0"
 rand = "0.4"
+rbx_binary = "0.2.0"
+rbx_tree = "0.2.0"
+rbx_xml = "0.2.0"
 regex = "1.0"
 reqwest = "0.9.5"
 rouille = "2.1"
@@ -35,11 +38,10 @@ serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
 uuid = { version = "0.7", features = ["v4", "serde"] }
-rbx_tree = "0.2.0"
-rbx_xml = "0.2.0"
-rbx_binary = "0.2.0"
 
 [dev-dependencies]
 tempfile = "3.0"
 walkdir = "2.1"
-lazy_static = "1.2"
+lazy_static = "1.2"
+pretty_assertions = "0.5.1"
+paste = "0.1"