feat(alertmanager): integrate with ruler (#7222)

### Summary

Integrate the new implementations of the alertmanager along with changes to the ruler. This change can be broadly categoried into 3 parts:

#### Frontend
- The earlier `/api/v1/alerts` api was double encoding the response in json and sending it to the frontend. This PR fixes the json response object. 

For instance, we have gone from the response `{
    "status": "success",
    "data": "{\"status\":\"success\",\"data\":[{\"labels\":{\"alertname\":\"[platform][consumer] consumer is above 100% memory utilization\",\"bu\":\"platform\",\"......
}` to the response `{"status":"success","data":[{"labels":{"alertname":"[Metrics] Pod CP......`

- `msteams` has been changed to `msteamsv2` wherever applicable

#### Ruler
The following changes have been done in the ruler component:

- Removal of the old alertmanager and notifier
- The RuleDB methods `Create`, `Edit` and `Delete` have been made transactional
- Introduction of a new `testPrepareNotifyFunc` for sending test notifications
- Integration with the new alertmanager

#### Alertmanager
Although a huge chunk of the alertmanagers have been merged in previous PRs (the list can be found at SigNoz/platform-pod#404), this PR takes care of changes needed in order to incorporate it with the ruler

- Addition of ruleId based matching
- Support for marshalling the global configuration directly from the upstream alertmanager
- Addition of orgId to the legacy alertmanager
- Support for always adding defaults to both routes and receivers while creating them
- Migration to create the required alertmanager tables
- Migration for msteams to msteamsv2 has been added. We will start using msteamv2 config for the new alertmanager and keep using msteams for the old one.

#### Related Issues / PR's

Closes SigNoz/platform-pod#404
Closes SigNoz/platform-pod#176

feat(alertmanager): create config on first user creation

feat(msteams): add migration for msteams

feat(config): add Yamlv2Unmarshaller func

feat(msteams): add migration for msteams

test(matcher): add test cases for matcher

feat(msteams): add migration for msteams

chore: add new user preferences for welcome checklist (#7239)

fix(alertmanager): fix ReceiverNamesFromRuleID logic

fix(alertmanager): let defaults kick in for the receiver