Move Prometheus exporter to ROCK

[gtrkiller]

Applicable spec:

Overview

Install the Apache Prometheus exporter into Wordpress' ROCK

Rationale

This change simplifies the architecture of the charm by reducing the amount of resources and containers it needs

Juju Events Changes

N/A

Module Changes

N/A

Library Changes

N/A

Checklist

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

[github-actions[bot]]

Test coverage for e7239ab6c47c3f4fab06d65b01bc3fe4b1769078

Name                Stmts   Miss Branch BrPart  Cover   Missing
---------------------------------------------------------------
src/charm.py          540     35    182     32    91%   186-189, 353-354, 413->417, 566, 597, 603, 620-624, 654, 689-690, 747, 756, 860->865, 864, 866, 871-872, 932, 950, 957, 1047, 1056, 1068, 1089, 1098, 1117, 1121, 1150, 1203, 1335, 1357, 1364->1366, 1409->exit, 1421, 1437, 1474
src/cos.py             15      0      0      0   100%
src/exceptions.py      17      1      2      1    89%   41
src/state.py           34      0      4      0   100%
src/types_.py          16      0      0      0   100%
---------------------------------------------------------------
TOTAL                 622     36    188     33    91%

Static code analysis report

Run started:2024-01-18 13:11:08.699498

Test results:
    No issues identified.

Code scanned:
    Total lines of code: 4424
    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):