Commandline and REPL to automatically delete session

[InfImpDrive]

Describe the solution you'd like

There is already ways to create a session both by command line and via REPL:

aichat --session TEST_SESSION --save-session

However, there seems to be no way to do targeted deletion of named sessions.
Could be any of:

aichat --session TEST_SESSION --delete-session
or
aichat --delete TEST_SESSION
or
other similar (And equivalent REPL that automatically deletes a known specific named session).

Additional context

This is useful for scripts that create a session automatically. In many cases, it is preferable to clear the existing named session (from a previous script run) before beginning a new session that is carried across a series of aichat commands.

[sigoden]

It is recommended to locate the sessions_dir and then delete the session YAML files to remove the sessions.

Alternatively, create a completely new temp directory each time as the sessions_dir.

AICHAT_SESSIONS_DIR=/tmp/sessions01 aichat 

[sigoden]

This paradigm applies to roles, sessions, rags, and agents.

[sigoden]

Since #922 merged, you can use --empty-session instead of deleting the session.