ISD-2184 Add http interface module with provider and requirer class implementation

[Thanhphan1147]

Applicable spec:

Overview

Rationale

Juju Events Changes

Module Changes

Library Changes

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)

[github-actions]

Test coverage for 53714a3

Name                      Stmts   Miss Branch BrPart  Cover   Missing
---------------------------------------------------------------------
src/charm.py                 54     18      4      0    62%   59-60, 64-65, 70, 79-92, 100, 105-106, 111-114
src/haproxy.py               54     19      6      2    62%   62, 73-76, 92-98, 109-113, 121-125
src/http_interface.py        43     20      4      0    49%   26-28, 35, 43-44, 94-97, 113-122
src/state/config.py          22      8      6      0    57%   44-52, 64-65
src/state/tls.py             36     12      8      1    61%   58-75, 92->exit
src/state/validation.py      26     12      4      0    47%   57-69
src/tls_relation.py          57      1     10      1    97%   57
---------------------------------------------------------------------
TOTAL                       292     90     42      4    65%

Static code analysis report

Run started:2024-08-16 14:28:30.644129

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 871
  Total lines skipped (#nosec): 0
  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):

[Thanhphan1147]

closing as dups to #14, will be reused when implementing haproxy-route integration