feat: add InitialView configuration option to k9s

[uozalp]

This pull request introduces a new configuration setting called initialView that allows users to specify the initial view in the application. The changes span across multiple files to integrate this new setting into the application logic, configuration, and documentation.

Configuration and Documentation Updates:

• README.md: Added a description of the initialView setting to the configuration section.
• internal/config/json/schemas/k9s.json: Added initialView as a new string type configuration option.

Application Logic Updates:

• cmd/root.go: Modified the run function to set the active view based on the initialView configuration if it is specified.
• internal/config/k9s.go:
  • Added InitialView as a new field in the K9s struct.
  • Updated the Merge method to include merging the InitialView field.