fix(agent): Fix load db models error

[fangyinc]

Description

Ensure proper initialization of application modules and enhance the resource parameters handling for agent.

In this dbgpt/agent/resource/app.py#L34, the database is read in advance before it is initialized.

Closes #2184
Closes #2287
Closes #2163

How Has This Been Tested?

Clone a new DB-GPT project, run it with SQLite database.

Snapshots:

Include snapshots for easier review.

Checklist:

• My code follows the style guidelines of this project
• I have already rebased the commits and make the commit message conform to the project standard.
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• Any dependent changes have been merged and published in downstream modules

[cinjoseph]

LGTM~

[Aries-ckt]

LGTM

[csunny]

r+