Encapsulate dependencies

[bbondy]

Related PRs:

• Adjust config for bat-native-ledger bat-native-anonize#1
• Adjust config for bat-native-ledger bat-native-tweetnacl#1
• Add config for bat-native-ledger bat-native-rapidjson#1
• Adjust config for bat-native-ledger bat-native-bip39wally-core#2
• Native ledger integration brave/brave-core#198

Fix #4
Fix #1

This PR includes the following changes:

• Encapsulates dependencies so they aren't included in header files forcing dependencies on others (The main thing being rapidjson)
• Fixes build configs (include_dirs should never need to be specified like it was, changed to just use deps)
• Forward declared some things to make headers include less headers. (which causes longer rebuild time)
• Fixed some formatting problems to be more consistent with brave + chromium coding guidelines:
  • No tabs, use 2 spaces instead (especially no mixing tabs and spacing)
  • Removes trailing whitespace on lines
  • Removes extra lines, especially those with only whitespace
  • Fixed spacing
  • Headers alphabetical
  • namespace end comment should be 2 spaces, then // then space then namespace
  • cc's header should be first.
  • accessor modifiers (public, private, protected, 1 space)
  • line continuations 4 spaces, or align parameters
• Fixed a complex type needs copy constructor error on a couple classes
• Fixed Code we write should have MPL 2.0 headers #1 header file using the correct license.