Fix OpenSSL system CA certificate issue in indico image

[weiiwang01]

In the current Indico image, the /etc/ssl/certs/ca-certificates.crt file is copied to the same location inside the Indico rock container. However, this is not a location recognized by OpenSSL as the system CA certificates. Consequently, this causes Python, which depends on OpenSSL, to fail in establishing TLS connections, particularly as observed in the smtplib library.

Update the rockcraft.yaml file to copy the ca-certificates.crt to /usr/lib/ssl/cert.pem, which is OpenSSL's default SSL certificate file on Ubuntu.

[github-actions]

Test coverage for 85b7990

Name                       Stmts   Miss Branch BrPart  Cover   Missing
----------------------------------------------------------------------
src/charm.py                 329      9     82      7    96%   631, 672-673, 761->777, 763->772, 772->777, 785-786, 825, 858->exit, 896-902
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                        480      9     96      7    97%

Static code analysis report

Run started:2024-06-05 12:49:58.154962

Test results:
  No issues identified.

Code scanned:
  Total lines of code: 2970
  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):