support size-in-bytes type

[carueda]

Support a size type corresponding to the size-in-bytes formats supported by Typesafe-Config as specified in https://github.com/typesafehub/config/blob/master/HOCON.md#size-in-bytes-format

Example config spec for tscfg to process:

# required size
sizeReq: "size"

# optional size, no default
sizeOpt: "size?"

# optional size with default value 1024 bytes
sizeOptDef: "size | 1K"

# list of sizes
sizes: [ size ]

# list of lists of sizes
sizes2: [ [ size ] ]

Input config example:

sizeReq = "2048K"
sizeOpt = "1024000"
sizes = [ 1000, "64G", "16kB" ]
sizes2  = [[ 1000, "64G" ], [ "16kB" ] ]