Create backup action

[javierdelapuente]

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 - Manging 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]

Lint checks failed for 10b3136

```

/home/ubuntu/github-runner/_work/synapse-operator/synapse-operator/src/backup.py:345 in public function default_filenames_to_backup:
D103: Missing docstring in public function

[github-actions]

Test coverage for 10b3136

Name                            Stmts   Miss Branch BrPart  Cover   Missing
---------------------------------------------------------------------------
src/actions/__init__.py             3      0      0      0   100%
src/actions/register_user.py       22      0      2      0   100%
src/actions/reset_instance.py      21      0      2      0   100%
src/backup.py                     165     11     38      4    91%   85, 250, 327->329, 333->exit, 346-349, 366-371
src/backup_observer.py             51      6      2      0    89%   53-55, 75-77
src/charm.py                      222      8     50      4    96%   165-166, 227-228, 247-248, 289, 303
src/charm_state.py                 63      1     10      1    97%   127
src/charm_types.py                 21      0      2      0   100%
src/database_client.py             53      1     10      3    94%   35, 47->exit, 69->exit
src/database_observer.py           48      4      4      0    92%   69-71, 87
src/exceptions.py                   4      1      0      0    75%   22
src/mjolnir.py                     76      6     20      1    91%   60-64, 73
src/observability.py                9      0      0      0   100%
src/pebble.py                      96     12     16      6    84%   91-92, 94-95, 103, 105, 107, 111, 132-133, 148-149
src/saml_observer.py               45      1      8      0    98%   64
src/smtp_observer.py               70      3     14      1    95%   70-74, 96->101
src/synapse/__init__.py             3      0      0      0   100%
src/synapse/api.py                161      2     22      2    98%   207, 376
src/synapse/workload.py           262      8     42      6    95%   388->exit, 417-418, 470-471, 507-508, 524, 573->576, 622, 630->632, 632->634
src/user.py                        24      0      4      0   100%
---------------------------------------------------------------------------
TOTAL                            1419     64    246     28    94%
Coverage failure: total of 94 is less than fail-under=95

Static code analysis report

Run started:2024-01-26 17:13:49.054653

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 7216
  Total lines skipped (#nosec): 4
  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):

[javierdelapuente]

Closed in favour of a new alternative using external programs in the workload.

[javierdelapuente]

maximum 10000 parts

[javierdelapuente]

test