Create a rockfile to replace the current Dockerfile

[nrobinaubertin]

Overview

The goal of this PR is to replace the current dockerfile with a rockfile.

Notes:

• I decided to not use a bare base, opting for simplicity for now. In the same spirit, I'm using the root user at runtime.
• The integration tests rely on this draft PR so that means that it's not really mergeable until the latter is.
• Integration tests rely on raise_on_error=False sometimes, I want to work on this in a further PR.

Checklist

• The charm style guide was applied
• The contributing guide was applied
• The changes are compliant with ISD054 - Managing Charm Complexity
• The documentation is generated using src-docs
• The documentation for charmhub is updated.
• The PR is tagged with appropriate label (urgent, trivial, complex)

[arturo-seijas]

LGTM

[github-actions]

Test coverage for 6789e5d

Name              Stmts   Miss Branch BrPart  Cover   Missing
-------------------------------------------------------------
src/charm.py        250     17     70      9    92%   128, 137, 145, 285->290, 484-486, 529-531, 534->exit, 541-542, 544->exit, 551, 579-585, 611->exit, 625-626
src/database.py      30      1      8      1    95%   56
-------------------------------------------------------------
TOTAL               280     18     78     10    92%

Static code analysis report

Run started:2023-09-14 12:30:08.627269

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 1775
  Total lines skipped (#nosec): 1
  Total potential issues skipped due to specifically being disabled (e.g., #nosec BXXX): 0

Run metrics:
  Total issues (by severity):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
  Total issues (by confidence):
  	Undefined: 0
  	Low: 0
  	Medium: 0
  	High: 0
Files skipped (0):