Merge bitcoin#16386: depends: disable unused Qt features

248e22b depends: disable unused Qt features (fanquake)

Pull request description:

  Related to bitcoin#16354. Kept separate from bitcoin#16370, because:

  > QT is a monster 😂 - dongcarl in #bitcoin-builds

  I've done some basic testing on `macOS 10.14` and `Debian 9.9` so far. Would be good to have someone test on Windows.

  I was thinking about adding some inline documentation, i.e info about where to find the lists of Qt features & libraries, as well as breaking the flags up so that it's clearer which libraries we are supplying, which we rely on Qt for etc. Could go towards addressing  some of`2` in bitcoin#16354.

ACKs for top commit:
  sipsorcery:
    tACK 248e22b (Windows 10 test only)
  laanwj:
    ACK 248e22b

Tree-SHA512: 2cdcea8d268de21d355a7625c4d352f65728df0b8d8cc0f396aca676f42099a819f95652dfbfc665c991ba12c52735c1e9b693df4b12e3ee178fd39356fba8e0

depends/packages/qt.mk

@@ -35,6 +35,7 @@ $(package)_config_opts += -no-freetype
 $(package)_config_opts += -no-gif
 $(package)_config_opts += -no-glib
 $(package)_config_opts += -no-icu
+$(package)_config_opts += -no-ico
 $(package)_config_opts += -no-iconv
 $(package)_config_opts += -no-kms
 $(package)_config_opts += -no-linuxfb
@@ -70,19 +71,36 @@ $(package)_config_opts += -system-zlib
 $(package)_config_opts += -static
 $(package)_config_opts += -silent
 $(package)_config_opts += -v
+$(package)_config_opts += -no-feature-bearermanagement
+$(package)_config_opts += -no-feature-colordialog
+$(package)_config_opts += -no-feature-commandlineparser
+$(package)_config_opts += -no-feature-concurrent
 $(package)_config_opts += -no-feature-dial
+$(package)_config_opts += -no-feature-filesystemwatcher
+$(package)_config_opts += -no-feature-fontcombobox
 $(package)_config_opts += -no-feature-ftp
+$(package)_config_opts += -no-feature-image_heuristic_mask
+$(package)_config_opts += -no-feature-keysequenceedit
 $(package)_config_opts += -no-feature-lcdnumber
 $(package)_config_opts += -no-feature-pdf
-$(package)_config_opts += -no-feature-printer
 $(package)_config_opts += -no-feature-printdialog
-$(package)_config_opts += -no-feature-concurrent
+$(package)_config_opts += -no-feature-printer
+$(package)_config_opts += -no-feature-printpreviewdialog
+$(package)_config_opts += -no-feature-printpreviewwidget
+$(package)_config_opts += -no-feature-regularexpression
+$(package)_config_opts += -no-feature-sessionmanager
 $(package)_config_opts += -no-feature-sql
 $(package)_config_opts += -no-feature-statemachine
 $(package)_config_opts += -no-feature-syntaxhighlighter
 $(package)_config_opts += -no-feature-textbrowser
 $(package)_config_opts += -no-feature-textodfwriter
+$(package)_config_opts += -no-feature-topleveldomain
 $(package)_config_opts += -no-feature-udpsocket
+$(package)_config_opts += -no-feature-undocommand
+$(package)_config_opts += -no-feature-undogroup
+$(package)_config_opts += -no-feature-undostack
+$(package)_config_opts += -no-feature-undoview
+$(package)_config_opts += -no-feature-vnc
 $(package)_config_opts += -no-feature-wizard
 $(package)_config_opts += -no-feature-xml
 
@@ -101,7 +119,6 @@ $(package)_config_opts_linux += -qt-xcb
 $(package)_config_opts_linux += -no-xcb-xlib
 $(package)_config_opts_linux += -no-feature-xlib
 $(package)_config_opts_linux += -system-freetype
-$(package)_config_opts_linux += -no-feature-sessionmanager
 $(package)_config_opts_linux += -fontconfig
 $(package)_config_opts_linux += -no-opengl
 $(package)_config_opts_arm_linux += -platform linux-g++ -xplatform bitcoin-linux-g++