feat: Allow SQL tap developers to leverage post_process

[BuzzCutNorman]

Gives SQL Streams the ability to utilize the Core Stream post_process method out of the box just like REST Streams.

Closes #1674

---

📚 Documentation preview 📚: https://meltano-sdk--1681.org.readthedocs.build/en/1681/

[kgpayne]

Thanks @BuzzCutNorman 🙌 Out of interest, do you have a link to a Tap where you are using or want to use this functionality? What kinds of transforms are you doing?

[codecov]

Codecov Report

Merging #1681 (0e689c4) into main (1583937) will decrease coverage by 0.04%.
The diff coverage is 50.00%.

❗ Current head 0e689c4 differs from pull request most recent head ab319af. Consider uploading reports for the commit ab319af to get more accurate results

@@            Coverage Diff             @@
##             main    #1681      +/-   ##
==========================================
- Coverage   85.11%   85.08%   -0.04%     
==========================================
  Files          59       59              
  Lines        4865     4868       +3     
  Branches      806      807       +1     
==========================================
+ Hits         4141     4142       +1     
- Misses        526      527       +1     
- Partials      198      199       +1     

Impacted Files	Coverage Δ
singer_sdk/streams/sql.py	86.36% <50.00%> (-2.53%)	⬇️

📣 We’re building smart automated test selection to slash your CI/CD build times. Learn more

[BuzzCutNorman]

@kgpayne I am using this in my tap-mssql variant. Here is the link to the post_process method in tap-mssql.
https://github.com/BuzzCutNorman/tap-mssql/blob/e1a877df2c30f5fb7bbdec37873459f3af8f56e9/tap_mssql/client.py#L408. I am doing a date fix and encoding binary strings.

[edgarrmondragon]

Thanks @BuzzCutNorman!