6971e79 gui: add Direction column to peers tab (Jon Atack)

Pull request description:

  Picking up #289

  This adds a `Direction column`, making the peers tab the same as the `Direction/Type` row in the peer details and the direction and type columns in our other user-facing peer connections table in `-netinfo`.

  Users can now sort the peers table by direction. The default sort is set to inbound, then outbound.

  | Master        | PR               |
  | ----------- | ----------- |
  | ![Screen Shot 2021-05-05 at 3 51 09 AM](https://user-images.githubusercontent.com/23396902/117111864-38ff9a00-ad56-11eb-889d-f1c838c845e6.png) | ![Screen Shot 2021-05-05 at 3 35 40 AM](https://user-images.githubusercontent.com/23396902/117111892-4157d500-ad56-11eb-82b1-5bd3e88a4cff.png) |

ACKs for top commit:
  jonatack:
    Tested ACK 6971e79
  ShaMan239:
    tACK 6971e79
  hebasto:
    ACK 6971e79, tested on Linux Mint 20.2 (Qt 5.12.8).

Tree-SHA512: 9716cdedd435f88245a097fed6d4b2b486104d0dd09df739bdb4f2bfad709cbd9c9a231168cc3326e94fa5fddc77dd68f992f20417d04d94930db9fccdbb7de1

4832737 qt: connection type translator comments (Jarol Rodriguez)

Pull request description:

  This PR introduces Qt translator comments for `Connection Type` strings in `guiutil.cpp` as well as `rpcconsole.cpp`.

  This is an alternate implementation of the idea presented in the last three commits of #289. It is especially inspired by commit 842f4e834dfe5fd2786a5092f78ea28da1b36e4f.

  Per [Qt Dev Notes](https://github.com/bitcoin-core/bitcoin-devwiki/wiki/Developer-Notes-for-Qt-Code), it is better to not break up strings when not necessary. This way we preserve the full context for translators.

ACKs for top commit:
  jonatack:
    Code review re-ACK 4832737 per `git diff 371e2b9 4832737`, changes are translator comment edits since my review yesterday (thank you for updating)
  hebasto:
    ACK 4832737

Tree-SHA512: 67e1741e10a2e30cde6d50d3293eec89f0b7641b34463865dc6909d2926cdcf33a7d8c1dc8055d2f85906ad2002cdaa594d37b184d16e2f06614b6c5ad00c982