Add GMR consumer for ASB that has no implementation so we can test consumption in DEV

[tjpeel-ee]

As per PR title.

This PR is purely scaffolding with an integration test to prove the GMR message is being raised and consumed.

BTMS front end config added via DEFRA/btms-frontend#27
App config added via https://github.com/DEFRA/cdp-app-config/pull/907

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

See analysis details on SonarQube Cloud

[github-actions]

Package	Line Rate	Branch Rate	Health
Btms.Consumers	85%	77%	✔
Btms.Azure	43%	100%	❌
Btms.Business	82%	75%	✔
Btms.Types.Alvs.Mapping.V1.Tests	0%	0%	❌
Btms.Types.Ipaffs	95%	62%	✔
Btms.Types.Gvms	67%	100%	➖
Btms.Types.Alvs.Mapping	81%	0%	✔
Btms.Backend	62%	39%	➖
Btms.Types.Gvms.Mapping	38%	26%	❌
Btms.Model	92%	94%	✔
Btms.Common	74%	56%	➖
TestGenerator.IntegrationTesting.Backend	83%	71%	✔
TestDataGenerator	86%	78%	✔
Btms.Types.Ipaffs.Mapping	77%	50%	➖
Btms.BlobService	39%	27%	❌
Btms.Metrics	84%	0%	✔
Btms.Backend.Data	64%	58%	➖
Btms.Analytics	74%	73%	➖
Btms.Types.Alvs	85%	67%	✔
Btms.SensitiveData	79%	83%	➖
Btms.SyncJob	63%	45%	➖
Btms.Emf	11%	0%	❌
Summary	78% (9950 / 12682)	64% (1003 / 1573)	➖