chore(docs): Updated Index and Tutorial docs

[alithethird]

Applicable spec:

Overview

Standarise the Indico tutorial with other tutorials and improve/fix the tutorial.
Update the Indico index.md to standardise it with the other charms.

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)

[erinecon]

Both pages look great -- thank you for working on them!

[yanksyoon]

Minor suggestions, LGTM thank you!

[erinecon]

LGTM

[github-actions]

Test coverage for c43c140

Name                       Stmts   Miss Branch BrPart  Cover   Missing
----------------------------------------------------------------------
src/charm.py                 349     12     86      8    95%   404, 418-419, 669, 710-711, 802->818, 804->813, 813->818, 826-827, 866, 899->exit, 937-943
src/database_observer.py      32      0      4      0   100%
src/s3_observer.py            17      0      0      0   100%
src/saml_observer.py          14      0      0      0   100%
src/smtp_observer.py          15      0      0      0   100%
src/state.py                  73      0     10      0   100%
----------------------------------------------------------------------
TOTAL                        500     12    100      8    97%

Static code analysis report

Run started:2024-10-07 13:06:05.948800

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 3113
  Total lines skipped (#nosec): 2
  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):

[amandahla]

LGTM