Tracking issue of default value support for columns

[ygf11]

Describe This Problem

Support default value for columns in Ceresdb.

Proposal

Support default value:

• Column default value option can be a normal Expr.
• Column can reference other columns, regardless what defining orders they are.

As @ShiKaiWi and @jiacai2050 suggest, the full feature is complex, I split it into some small tasks.

• [x] https://github.com/CeresDB/ceresdb/issues/249
• [x] https://github.com/CeresDB/ceresdb/issues/250
• [ ] https://github.com/CeresDB/ceresdb/issues/251
• [ ] https://github.com/CeresDB/ceresdb/issues/259

Additional Context

original issue:

• [ ] https://github.com/CeresDB/ceresdb/issues/210