Spektate dashboard should allow certain columns to be hidden/shown

[samiyaakhtar]

As a: developer

I want: to hide some columns that don't apply to my project

So that: I can customize the dashboard to the needs of my project

Describe the solution you'd like:
Currently, we show all columns for all configurations. We want to support modification of this configuration to allow certain columns to be hidden. For eg. a user may want to hide the Approval PR and merged by column if they don't have PRs going into their HLD (or a custom HLD config).

• Support the use of a config file, if present, should modify the visibility of columns. By default, all columns are to be shown, unless specified in this config file.
• Provide guidance in documentation on how to enable this

Acceptance Criteria:
Dashboard columns are more customizable

Describe alternatives you've considered:
Leave as is

Additional context:

Does this require updates to documentation?: Yes