add darksend balance to getinfo

… window without loaded wallets

7b2e42e qt: Add WalletFrame::sizeHint (Hennadii Stepanov)

Pull request description:

  This PR fixes a bug in master (d67883d) and in 0.20.1 that could be easily reproduced with
  ```
  $ src/qt/bitcoin-qt -regtest -resetguisettings -nowallet
  ```

  ![Screenshot from 2020-10-25 21-21-27](https://user-images.githubusercontent.com/32963518/97117179-b1800100-170a-11eb-87c9-3120d39b9455.png)
  ![Screenshot from 2020-10-25 21-23-32](https://user-images.githubusercontent.com/32963518/97117186-b644b500-170a-11eb-8b5d-234ff7205003.png)

  **With this PR:**

  ![Screenshot from 2020-10-25 21-20-35](https://user-images.githubusercontent.com/32963518/97117226-f441d900-170a-11eb-8d66-98b7718a2bb1.png)
  ![Screenshot from 2020-10-25 21-23-03](https://user-images.githubusercontent.com/32963518/97117232-f99f2380-170a-11eb-85ed-c7b5ece926b2.png)

  ---

  Fix dashpay#104
  Fix dashpay#113

  This PR is an alternative to dashpay#107 without [hard-coding a size in pixels](bitcoin-core/gui#107 (comment)).

ACKs for top commit:
  jonasschnelli:
    Tested ACK 7b2e42e - I can confirm this fixes dashpay#104 (Ubuntu 20.04 - HiDPI 200%).

Tree-SHA512: eb0692dbeb3befdeecca0e41534c9783eab6637c14cc4f170ee42619235884f9354f8d22a10c20c08cc89dc5340a60b7dfa2523c12e64b3386b3fd2c6d5f934e

7e747e8a07 Merge pull request dashpay#105 from kwvg/bump_1.3.4
f8703c9971 chore: bump version to 1.3.4
5cc55ce222 Merge pull request dashpay#104 from UdjinM6/fix_gmp_freebsd
aad89e3e86 Merge pull request dashpay#103 from kwvg/pyci_upd
a52d7ed109 Merge pull request dashpay#102 from kwvg/autoconf
56b2d4a0ac ci: replace EoL Go 1.17 with 1.22
17f3ab47a0 ci: drop EoL Python 3.7 and 3.8, replace with Python 3.12
a3fcdde7c5 fix: gmp detection on FreeBSD
e73acdd304 build: consolidate `TARGET_OS` assignments into `OPSYS` assignment case
343c6244ac build: remove unnecessary `BUILD_`{`BENCH`, `TEST`} variables
af9a6906c3 build: account for FreeBSD's `amd64` `host_cpu` in optim. CPU detection
34a7c60e86 build: replace `bash`-isms with `sh`-friendly `test` and `case`

git-subtree-dir: src/dashbls
git-subtree-split: 7e747e8a0769f6e4d308d8d2e3dd254c240cbdd9