Updates for daily loading, kibo, sqlalchemy 2.

[weaverba137]

This PR:

• Updates SQLAlchemy code to SQLAlchemy 2 (now installed at NERSC).
• Add a convert() method to database objects (ORM classes). Basically each table knows how to convert data tables into database objects.
• Adds some configuration needed to load kibo.
• Adds support for tile-based loading, which will be needed to support loading daily.
• Adds code for patching daily exposure and tile files based on another specprod.

Note that there is some remaining work to be done:

• Remove redundant code now that all database objects have a convert() method. This should be included in this PR.
• Some additional work is needed to support tile-based updates (in the SQL UPDATE sense). This may or may not end up being included in this PR.

[weaverba137]

PS, some additional testing is needed to ensure that any tag resulting from this PR can support guadalupe and iron.

If kibo requires additional columns, for example, that should be a separate PR and tag.

[weaverba137]

Also make sure to keep the tests in #12 in mind. To recap:

• If one or more tables in a given specprod schema contain columns that are not described by the associated ORM object(s), that's OK.
• If one or more ORM objects describe columns that are not in an associated table in a given specprod schema, that's BAD.

In other words, if we have to add columns for kibo, we have to preserve a version that does not have those columns in order to work with iron.

Finally, we may need to preserve an environment that contains SQLAlchemy 1.x in order to work with fuji.

[weaverba137]

Note: this PR, changes the size of Exposure.goaltype and Tile.goaltype relative to iron. Make sure this change works with iron. There should not be any other column changes relative to iron in this PR. If necessary, revert those changes for the purposes of making a DR1 tag, then update the sizes for kibo.

[weaverba137]

I tested iron with an updated tutorial notebook. Based on that, I'm going to merge and tag a version that we know still works with both iron and SQLAlchemy 2.