improve sonar analysis adding provider (github or gitlab)

[vdelendik]

sonar onPR or onPush evens analysis should specify explicitly
sonar.pullrequest.provider=...
default value in groovy pipeline code: Github

But if current job has GITHUB_HOST=gitlab.com we have to specify
sonar.pullrequest.provider=GitlabServer

for bitbucket
sonar.pullrequest.provider=BitbucketServer

[vdelendik]

done: https://github.com/qaprosoft/qps-pipeline/pull/872/files

[vdelendik]

Sandino: I recommend to move it to the 5.3/1.2 release because as of now the gitlab webhooks config its done manually, it was tested with some random freestyle project and not with our pipeline

[sandinosanchez]

This ticket is verified against #5 test steps.