Generic DB schema change writer PoC

What does this MR do and why?

This MR adds annotations to common schema statements that will need to be propagated to downstream database systems:

• add column
• remove column
• swap column

Currently the generic migration is written to STDOUT:

{
  "table": "issues",
  "schema": "public",
  "operation": {
    "identifier": "add_column",
    "name": "my_col1",
    "type": "int64",
    "default": 1
  }
}


{
  "table": "issues",
  "schema": "public",
  "operation": {
    "identifier": "add_column",
    "name": "my_col1",
    "type": "int64",
    "default": 1
  }
}

{
  "table": "issues",
  "schema": "public",
  "operation": {
    "identifier": "swap_columns",
    "column1": "my_col1",
    "column2": "my_col2"
  }
}

TODO:

• Record the changes within the migration file in a variable.
• Generate a generic migration file (json?) per migration file: 1 file can contain multiple changes
• Apply these changes automatically to CH
• Tests

References

Screenshots or screen recordings

Before	After

How to set up and validate locally

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