text: Title: Add utlity functions to get URLs of dashboards for specific KPIs
  Body: ## Tell us about the problem you're trying to solve
  
  Currently, URLs to KPIs are constructed directly in f-strings using the URL prefix. This leads to repetition of the same code across many files and any change in the URL needs to be changed at all places. For example: https://github.com/chaos-genius/chaos_genius/blob/04cfe2ee0e82ff627fa29f8f50ccc08b6ba52bef/chaos_genius/alerts/base_alerts.py#L693
  
  ## Describe the solution you'd like
  
  - [ ] Create a new file `webapp_url.py` in `chaos_genius/utils/`
  - [ ] Add function to get the anomaly dashboard URL given KPI ID and Dashboard ID. `def anomaly_dashboard_url(kpi_id: int, dashboard_id: int = 0):`
  - [ ] Add function to get the DeepDrills dashboard URL given KPI ID and Dashboard ID. `def deepdrills_dashboard_url(kpi_id: int, dashboard_id: int = 0):`
  - [ ] Add function to get dashboard URL given dashboard ID. `def dashboard_url(dashboard_id: int = 0):`
  - [ ] Add function to get the anomaly edit URL given KPI ID and Dashboard ID. `def anomaly_edit_url(kpi_id: int, dashboard_id: int = 0):`
  
  ## Describe alternatives you've considered
  
  N/A
  
  ## Additional context
  
  Note: Dashboard ID 0 has all KPIs by default. KPIs cannot be deleted from this dashboard.
  
  ---
  
  Please leave a reply or reach out to us on our [community slack](https://github.com/chaos-genius/chaos_genius#octocat-community) if you need any help.
  