[Python] support partition spec in iceberg python library

[jun-he]

No description provided.

[nssalian]

@jun-he shall I work on this?

[nssalian]

This depends on the work in #3216 for types definition.

[jun-he]

Yep, working on #3216 and will ship it ASAP.

[nssalian]

Thanks @jun-he for starting off the work on python with #3234. I'll use this to open a PR for the partition_spec.

[nssalian]

@jun-he reason for closing this?

[jun-he]

Sorry, that was not intended. Reopened it.

[nssalian]

Thanks @jun-he. I should have a PR ready sometime next week.

[samredai]

Now that schema has been merged I think we need a couple more PRs in order to close this:

1. PartitionField
2. PartitionSpec
3. PartitionSpecBuilder

For 3. I know we discussed whether we should go with the builder pattern or just lean into python's ability for named optional arguments. There might be a middle ground in there where we use the builder pattern (to maintain consistency with the java codebase) and simply use that builder in the PartitionSpec dunder init.

Anyone interested, please feel free to tackle any of these items! 😃

[dramaticlly]

I can help by starting with PartitionSpec!

[rdblue]

This was added in the PRs above, so I'll close this.