Add ALTER COLUMN operations (#390)

Covers the column manipulations mentioned in
https://clickhouse.com/docs/en/sql-reference/statements/alter/column to
be written declaratively in migration.

1. [ADD
COLUMN](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#add-column)
- AlterTableAddColumn
2. [DROP
COLUMN](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#drop-column)
- AlterTableDropColumn
3. [RENAME
COLUMN](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#rename-column)
- this operation is not supported. Renaming the column is a two-step
process. See
[here](https://www.notion.so/signoz/CH-Mutations-aware-schema-migrations-80a19988fd5a4558afa1e5d5de5cc57e?pvs=4#a63ad5338acb4388a66c0b3293ffdac9)
4. [CLEAR
COLUMN](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#clear-column)
- we don't need this now but can be added later.
5. [COMMENT
COLUMN](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#comment-column)
- same
6. [MODIFY
COLUMN](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#modify-column)
- AlterTableModifyColumn
7. [MODIFY COLUMN
REMOVE](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#modify-column-remove)
- AlterTableModifyColumnRemove
8. [MODIFY COLUMN MODIFY
SETTING](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#modify-column-modify-setting)
- AlterTableModifyColumnModifySettings
9. [MODIFY COLUMN RESET
SETTING](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#modify-column-reset-setting)
- AlterTableModifyColumnResetSettings
10. [MATERIALIZE
COLUMN](https://clickhouse.com/docs/en/sql-reference/statements/alter/column#materialize-column)
- AlterTableMaterializeColumn