[BE2] Add parsing of RumorState messages

[DanielTavaresA]

Pending on #1877 .

Handles parsing from jsonRpc to usable object for new message RumorState

[github-actions]

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 ▀
	onsriahi14 🥉	5 ▀	3d 1h 48m	10 ▀
	matteosz	5 ▀	4d 40m	20 ▀
	arnauds5	4 ▀	7d 5h 54m ▀	12 ▀
	simone-kalbermatter	4 ▀	1d 14h 46m	0
	quadcopterman	4 ▀	5d 19h 9m ▀	1
	Tyratox	3 ▀	14d 6h 12m ▀	26 ▀▀
	1florentin	2	8d 13h 48m ▀	6
	t1b00	2	6d 6h 52m ▀	4
	osm-alt	2	6d 22h 53m ▀	12 ▀
	ljankoschek	2	18m	0
	DanielTavaresA	2	2d 10h 22m	8 ▀
	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
	emonnin-epfl	1	51m	1
⚡️ Pull request stats

[sonarqubecloud]

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

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[sonarqubecloud]

Quality Gate passed for 'PoP - Be2-Scala'

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66.7% Coverage on New Code
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[sonarqubecloud]

Quality Gate passed for 'PoP - Be1-Go'

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[sonarqubecloud]

Quality Gate passed for 'PoP - Fe1-Web'

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[sonarqubecloud]

Quality Gate passed for 'PoP - Fe2-Android'

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[K1li4nL]

LGTM !