feat(database): allow environment variables to override config.json

[yiweichi]

Purpose or design rationale of this PR

To allow database config file to be override using environmental variables.

PR title

Your PR title must follow conventional commits (as we are doing squash merge for each PR), so it must start with one of the following types:

• feat: A new feature

Deployment tag versioning

Has tag in common/version.go been updated or have you added bump-version label to this PR?

• Yes

Breaking change label

Does this PR have the breaking-change label?

• No, this PR is not a breaking change

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 25.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 51.60%. Comparing base (bce3383) to head (948d534).

Files with missing lines	Patch %	Lines
database/config.go	25.00%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #1517      +/-   ##
===========================================
- Coverage    51.61%   51.60%   -0.01%     
===========================================
  Files          155      155              
  Lines        12771    12775       +4     
===========================================
+ Hits          6592     6593       +1     
- Misses        5606     5608       +2     
- Partials       573      574       +1     

Flag	Coverage Δ
coordinator	17.22% <ø> (ø)
database	42.48% <25.00%> (-0.38%)	⬇️
rollup	55.37% <ø> (ø)

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