Feature/column position

[puzzledpolymath]

This pull request adds support for managing column position when altering a table and adding a column. Ticket #63 is what sparked interest for this feature.

🔍 What was changed

• ColumnInterface now includes methods isFirst and getAfter.
• ColumnInterface now defines getComment() explicitly rather than using annotations.
• AbstractColumn implements isFirst and getAfter, as well as setter methods first() and after.
• AbstractColumn returns sane values by default, leaving it up to driver implementations to store values.
• MySQLColumn stores values for first() and after methods. Being the only driver supporting this feature.

🤔 Why?

1. Precise control over column placement helps in maintaining a logical and organized schema.
2. Certain applications or legacy systems may expect columns in a specific order, and these options facilitate schema adjustments without extensive data migration.

📝 Checklist

• Closes #63
• How was this tested:
  • Unit tests added

📃 Documentation

$table->string('identifier')->nullable(false)->first();

$table->string('identifier')->nullable(false)->after('email');

[puzzledpolymath]

Feedback welcome. Once this gets finalized and merged, we can look at necessary changes for migration support.

[puzzledpolymath]

Adjustments have been made based on feedback, should now be good to merge.