[WIP] Adding an age column to deal with issue 330

[Bezbakri]

Fixes #330 .

Description of the Change

• Adding an age column as suggested in [Bug] blast age mistakenly reported as log_age in data mode #330 (comment)
• Copied data from the log_age columns to the new age columns
• Noted the change down in the documentation on the web_api page

Checklist

Please check all that apply to your proposed changes

• HTML code change
• Added package dependency
• Added data
• Changed django model
• Documentation change
• Added or changed TaskRunner

Additional context

[manning-ncsa]

Please add a commit updating the app version and changelog.

[manning-ncsa]

Any reason why this is done in two steps instead of directly assigning in one step?

[manning-ncsa]

To test your migration,

1. Start a dev deployment from scratch (you don't have redownload the required files) from v1.9.5.
2. Stop the deployment and checkout your feature branch with the migration script.
3. Restart the deployment and query the database to verify effect. To query the database, add a function to app/host/management/commands/util.py that can be invoked as shown here. This will allow me to easily verify your test myself. We may choose to remove the test function prior to merging to main.

[manning-ncsa]

Here is the procedure I used to test the export/import of transient datasets between the current and proposed version:

# Stop Blast and clear database
bash run/blastctl full_dev purge-db

# Checkout v1.9.4
git checkout v1.9.4
git status --porcelain

# Start Blast
bash run/blastctl full_dev up

# Export 2026dgt via web page

# Stop Blast and checkout new version
bash run/blastctl full_dev down
git checkout rishabh-logage 
bash run/blastctl full_dev up

# Delete transient 2026dgt http://localhost:4000/api/transient/delete/2026dgt/all

# Import 2026dgt from exported archive file

# Export 2026dgt again to compare with original and verify that the new "age" keys exist:
#     ...
#     "log_age_16": 0.5585912229223885,
#     "log_age_50": 4.792816941415436,
#     "log_age_84": 7.2754636677303886,
#     "age_16": 0.5585912229223885,
#     "age_50": 4.792816941415436,
#     "age_84": 7.2754636677303886,
#     ...

# Delete transient again http://localhost:4000/api/transient/delete/2026dgt/all

# Import 2026dgt from archive file exported by new version