Add support for more complex conditions

[gayanper]

Today we support simple conditions in breakpoints. To debug more complex programs some times we need more control over when the breakpoint should be active.
Eclipse has trigger points and IntelliJ has "Disable until hitting the following breakpoint"

So to keep things simple in vscode, but at the same time enable advance debugging features with some effort. Can we look at if it is possible to use condition with some special syntax.