qt: PluginsDialog: add link to website

Adds a link to the plugins.electrum.org website so users who open the
plugins dialog out of curiosity get guided to the website and can
discover other plugins and learn more about the system.

electrum/gui/qt/plugins_dialog.py

@@ -3,7 +3,7 @@ from functools import partial
 import shutil
 import os
 
-from PyQt6.QtWidgets import QLabel, QVBoxLayout, QGridLayout, QPushButton, QWidget, QScrollArea, \
+from PyQt6.QtWidgets import QLabel, QVBoxLayout, QHBoxLayout, QGridLayout, QPushButton, QWidget, QScrollArea, \
     QFormLayout, QFileDialog, QMenu, QApplication, QMessageBox
 from PyQt6.QtCore import QTimer
 
@@ -12,7 +12,8 @@ from electrum.gui import messages
 from electrum.logging import get_logger
 
 from .util import (WindowModalDialog, Buttons, CloseButton, WWLabel, insert_spaces, MessageBoxMixin,
-                   EnterButton, read_QIcon_from_bytes, IconLabel, RunCoroutineDialog)
+                   EnterButton, read_QIcon_from_bytes, IconLabel, RunCoroutineDialog, read_QIcon,
+                   webopen)
 
 
 if TYPE_CHECKING:
@@ -178,7 +179,15 @@ class PluginsDialog(WindowModalDialog, MessageBoxMixin):
         add_button = QPushButton(_('Add'))
         add_button.setMinimumWidth(40)  # looks better on windows, no difference on linux
         add_button.clicked.connect(self.add_plugin_dialog)
-        vbox.addLayout(Buttons(add_button, CloseButton(self)))
+        website_button = QPushButton(read_QIcon('globe.png'), _('Help'))
+        website_button.setToolTip(_('Visit plugins website'))
+        website_button.clicked.connect(lambda: webopen('https://plugins.electrum.org/'))
+        hbox = QHBoxLayout()
+        hbox.addWidget(website_button)
+        hbox.addStretch(1)
+        hbox.addWidget(add_button)
+        hbox.addWidget(CloseButton(self))
+        vbox.addLayout(hbox)
         self.show_list()
 
     def get_plugins_privkey(self) -> Optional['ECPrivkey']: