Stabilize resource management

This issue lists use-cases and thoughts related to them.

Reading resources

Proposed syntax:

val myResource by resource("text.csv").read()

test("…") {
    database().loadFrom(myResource())
}

Proposed module: compat-filesystem.

Using resources as expected values

Proposed syntax:

val myResource = resource("text.csv")

test("…") {
    val actual: String = …

    myResource.verify(actual)
}

There should be two different modes:

• By default: compares the contents of the file with the passed value.
• 'Write mode': writes the 'actual' value to the file, creating it if it doesn't exist. (useful when functionality changes)