[MINT-3227] API Support for deleting an MTO Milestone

[ClayBenson94]

MINT-3227

Description

• Adds API Support (GraphQL mutation) for deleting an MTO milestone
• Adds Postman Query
• Adds resolver test (honestly pretty minimal at this point, maybe could bolster this up)

Note

This PR also introduces a sqlutils.ExecProcedure method, useful for calling delete statements which do not need to return any values

How to test this change

1. Use scripts/dev db:seed to populate an MTO with some milestones
2. Optionally create some milestones from the common milestone library and link some solutions
3. Use the postman query to delete those milestones
   a. Ensure that the milestones are deleted properly
   b. Ensure that any milestone solution links are also deleted (but not the solutions themselves

PR Author Checklist

• I have provided a detailed description of the changes in this PR.
• I have provided clear instructions on how to test the changes in this PR.
• I have updated tests or written new tests as appropriate in this PR.
• Updated the Postman Collection if necessary.

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[StevenWadeOddball]

Thanks Clay! This looks good functionally. I didn't validate the cascade behavior. I have one slight change request regarding setting a session variable for the delete statement. That's needed for change history.

[StevenWadeOddball]

Thanks Clay! This looks good