Support paths (and similar strings) in stdin

[ninsbl]

It would be nice to be able to extract any string from module stdout and inject it to input to other parameters.
In particular, I am tinking of paths e.g. from g.tempfile, like e.g. here:

{
                    "list": [
                        {
                            "flags": "d",
                            "id": "g_tempfile",
                            "inputs": [
                                {
                                    "param": "pid",
                                    "value": "123456789"
                                }
                            ],
                            "module": "g.tempfile"
                        },
                        {
                            "flags": "g",
                            "id": "g_region",
                            "inputs": [
                                {
                                    "param": "raster",
                                    "value": "elevation"
                                }
                            ],
                            "module": "g.region"
                        },
                        {
                            "flags": "g",
                            "id": "r_univar",
                            "inputs": [
                                {
                                    "param": "map",
                                    "value": "elevation"
                                },
                                {
                                    "param": "output",
                                    "value": "g_tempfile::stdout/temporary_file.txt"
                                }
                            ],
                            "module": "r.univar"
                        }
                    ],
                    "version": "3"
                }

g_tempfile::stdout above process chain is not parsed.
Would it be sufficient to add e.g. / here:

actinia-core/src/actinia_core/core/common/process_chain.py

Line 66 in 0e3db9e

for delimiter in ["::", " ", "+", "-", "*", ":", "(", ")"]:

I am happy to create a PR.