Add jdbc drivers to Hop Web, fixes #4013

[hansva]

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[SaxenaShiv]

Hi, I have tried out the hop web docker image but I have still encountered an error related to the jdbc postgres driver support.

Error connecting to database [crateDB_cloud_service] :org.apache.hop.core.exception.HopDatabaseException: 
Error occurred while trying to connect to the database

Driver class 'org.postgresql.Driver' could not be found, make sure the 'PostgreSQL' driver (jar file) is installed.
Unable to load class 'org.postgresql.Driver' in this classloader or in the parent


org.apache.hop.core.exception.HopDatabaseException: 
Error occurred while trying to connect to the database

Driver class 'org.postgresql.Driver' could not be found, make sure the 'PostgreSQL' driver (jar file) is installed.
Unable to load class 'org.postgresql.Driver' in this classloader or in the parent


	at org.apache.hop.core.database.Database.normalConnect(Database.java:373)
	at org.apache.hop.core.database.Database.connect(Database.java:304)
	at org.apache.hop.core.database.DatabaseFactory.getConnectionTestReport(DatabaseFactory.java:47)
	at org.apache.hop.core.database.DatabaseFactory.getConnectionTestResults(DatabaseFactory.java:72)
	at org.apache.hop.core.database.DatabaseMeta.testConnectionSuccess(DatabaseMeta.java:2127)
	at org.apache.hop.ui.core.database.DatabaseMetaEditor.testConnection(DatabaseMetaEditor.java:901)
	at org.apache.hop.ui.core.database.DatabaseMetaEditor.test(DatabaseMetaEditor.java:764)
	at org.apache.hop.ui.core.database.DatabaseMetaEditor.lambda$createButtonsForButtonBar$6(DatabaseMetaEditor.java:956)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:109)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:687)
	at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:594)
	at org.eclipse.swt.widgets.Display.executeNextEvent(Display.java:1216)
	at org.eclipse.swt.widgets.Display.runPendingMessages(Display.java:1197)
	at org.eclipse.swt.widgets.Display.safeReadAndDispatch(Display.java:1180)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:1172)
	at org.eclipse.rap.rwt.application.AbstractEntryPoint.createUI(AbstractEntryPoint.java:69)
	at org.eclipse.rap.rwt.internal.lifecycle.RWTLifeCycle.createUI(RWTLifeCycle.java:177)
	at org.eclipse.rap.rwt.internal.lifecycle.RWTLifeCycle$UIThreadController.run(RWTLifeCycle.java:290)
	at java.base/java.lang.Thread.run(Thread.java:829)
	at org.eclipse.rap.rwt.internal.lifecycle.UIThread.run(UIThread.java:107)
Caused by: org.apache.hop.core.exception.HopDatabaseException: 
Driver class 'org.postgresql.Driver' could not be found, make sure the 'PostgreSQL' driver (jar file) is installed.
Unable to load class 'org.postgresql.Driver' in this classloader or in the parent

	at org.apache.hop.core.database.Database.connectUsingClass(Database.java:417)
	at org.apache.hop.core.database.Database.normalConnect(Database.java:358)
	... 19 more
Caused by: java.lang.ClassNotFoundException: Unable to load class 'org.postgresql.Driver' in this classloader or in the parent
	at org.apache.hop.core.plugins.HopURLClassLoader.loadClass(HopURLClassLoader.java:97)
	at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
	at org.apache.hop.core.database.Database.connectUsingClass(Database.java:392)
	... 20 more
Caused by: java.lang.ClassNotFoundException: org.postgresql.Driver
	at java.base/java.net.URLClassLoader.findClass(URLClassLoader.java:476)
	at org.apache.hop.core.plugins.HopURLClassLoader.loadClassFromThisLoader(HopURLClassLoader.java:67)
	at org.apache.hop.core.plugins.HopURLClassLoader.loadClass(HopURLClassLoader.java:92)
	... 22 more

Hostname:	cratedb-demo.aks1.eastus2.azure.cratedb.net
Port:	5432
Database name:	crate
Url:	jdbc:postgresql://cratedb-demo.aks1.eastus2.azure.cratedb.net:5432/crate