Add a method to read static roles in the database engine

[mimato]

Currently, the database backend does not provide a way to read static roles, only dynamic roles. This PR adds a method to read static roles as well.

Vault API doc: https://developer.hashicorp.com/vault/api-docs/secret/databases#read-static-role

[codecov]

Codecov Report

Merging #1009 (e7b63c1) into main (3b4e5ca) will increase coverage by 0.13%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##             main    #1009      +/-   ##
==========================================
+ Coverage   83.59%   83.72%   +0.13%     
==========================================
  Files          65       65              
  Lines        3023     2992      -31     
==========================================
- Hits         2527     2505      -22     
+ Misses        496      487       -9     

Impacted Files	Coverage Δ
hvac/api/secrets_engines/database.py	35.59% <33.33%> (-0.13%)	⬇️

... and 8 files with indirect coverage changes

[briantist]

Hi @mimato , welcome and thanks very much for this contribution! I was going to ask if you might be able to add tests for the new method... and then realized we don't have tests for this engine at all 😔 so I can't reasonably ask for that as a pre-requisite on this PR!

The code looks great though, if you're interested we have lots more we can use help with, thanks again!