run configuration: improve the way we handle bundle dir

[vgramer]

What would you like to be added

1. rename bundle to source directory in the UI� (using OPA doesn't mean you ever used bundles, so that concept may be unfamiliar.)
2. set the default value of bundleDir to the workspace directory. In the case where the project contains only opa files, it allows to eval / test policies in one click.

note: if bundleDir 's value is defined in the run configuration template, we must not overwrite it

[frangauthiercgi]

+1 on this

Here is my issue:
Our project is only used for OPA policies writing. To test we use the command opa test project_directory/ -v but we are unable to reproduce the same outcome using the plugin.
Bundle parameter seems mandatory and our tests are failing when specifying a Bundle path.
An option to set the bundle parameter as optional and using the project root as default would be appreciated.