Prepare karate for tests with multiple backends running at the same time

[4xiom5]

• Modified the karate Server classes to allow multiple server running at the same time.
• Updated both backends to add some missing configuration options

[github-actions[bot]]

Pull reviewers stats

Stats of the last 30 days for popstellar:		User	Total reviews	Time to review	Total comments
	K1li4nL 🥇	7 ▀	5d 1h 1m)) ▀	23 ▀▀
	pierluca 🥈	5 ▀	6d 22h 1m)) ▀	8 ▀
	matteosz 🥉	5 ▀	4d 40m))	20 ▀
	arnauds5	4 ▀	7d 5h 54m)) ▀	12 ▀
	onsriahi14	4 ▀	3d 3h 14m))	10 ▀
	quadcopterman	4 ▀	5d 19h 9m)) ▀	1
	Tyratox	3 ▀	14d 6h 12m)) ▀	26 ▀▀
	simone-kalbermatter	3 ▀	1d 3h 10m))	0
	1florentin	2	8d 13h 48m)) ▀	6
	t1b00	2	6d 6h 52m)) ▀	4
	osm-alt	2	6d 22h 53m)) ▀	12 ▀
	ljankoschek	2	18m))	0
	Kaz-ookid	2	7d 15h 16m)) ▀	7 ▀
	4xiom5	1	12d 4h 52m)) ▀	0
	sgueissa	1	2d 23h 56m))	1
	MariemBaccari	1	1d 16h 52m))	0
	DanielTavaresA	1	2d 19h 23m))	8 ▀

^{⚡️ Pull request stats}

[sonarcloud[bot]]

Quality Gate passed for 'PoP - PoPCHA-Web-Client'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[sonarcloud[bot]]

Quality Gate passed for 'PoP - Be2-Scala'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
50.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[sonarcloud[bot]]

Quality Gate passed for 'PoP - Be1-Go'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[sonarcloud[bot]]

Quality Gate passed for 'PoP - Fe1-Web'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[sonarcloud[bot]]

Quality Gate passed for 'PoP - Fe2-Android'

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud