[KATC] Update config schema

[RebeccaMahany]

This PR makes the following config updates:

• Rename source column to path to be more consistent with our e.g. dataflatten tables, which also return a path column
• Rename source to source_paths for clarity; additionally, make it an array rather than a single string to allow for matching against multiple patterns
• Rename query to source_query to disambiguate from the query column we use elsewhere
• Rename platform to filter to clarify that we may have other types of filters in the future
• Update config structure to be a list of tables instead of a map, so that K2 is able to send down config definitions for all tables instead of filtering by platform; launcher handles the filtering instead
• To support the above, move the table name inside the table config

These changes were made in roughly this order; it is possible to review commit-by-commit if that's easier.

[directionless]

I'm a little unsure about how pathConstraints will be used. Can you provide an example? (In this comment is fine, doesn't need to be docs)

[directionless]

I see what the code is doing, but I'm not sure it adds a lot over a pushing sourcePath through `filepath.Glob(...)

[RebeccaMahany]

Added documentation with an example

[directionless]

I think we probably want to future proof this a little.

Brainstorming... We could define a rich DSL with boolean logic. Or maybe we can just have a series of strings? Or maybe a series of K:V pairs? Early use might be goos:darwin or something?

[RebeccaMahany]

What about making filter into filters, a map[string]string? Simple to unmarshal and therefore parse, and flexible for future additions?

{
						"name": "kolide_indexeddb_leveldb_test",
						"source_type": "indexeddb_leveldb",
						"filters": {
						     "goos": "darwin"
						},
						"columns": ["data"],
						"source_paths": ["/some/path/to/db.indexeddb.leveldb"],
						"source_query": "db.store",
						"row_transform_steps": ["deserialize_chrome"]
					}

[directionless]

filters makes sense to me. I don't know if that should be an array of strings, or a map. Array might be little more flexible, I think either can work.

I think we should ponder whether that's an AND or an OR. If we go the way of overlays, this should be an AND, because the overlays handle OR

[RebeccaMahany]

I've updated to filters in the other PR #1772 -- if we decide to go with this approach I'll make the update here as well.

[RebeccaMahany]

Closing in favor of #1772