decouple manx from core

[uruwhy]

Description

• migrate manx's c_session.py to core code at app/contacts/utility/c_tcp_session.py (separate PR in manx plugin will remove the file as it will no longer be used)
• rename Session class from manx's c_session.py to TCPSession in case future classes are made for sessions based on other protocols (UDP, ICMP, etc)
• refactor session code to use read/write wrappers rather than accessing the internal reader/writer members of the Session class
• refactor session refresh to avoid deleting elements while iterating through a list
• better handling of empty/malformed response from session

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Ran caldera without manx plugin folder and confirmed it started fine.
Ran caldera with manx plugin and interacted with 1 and 2 sessions

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

[sonarqubecloud]

❌ The last analysis has failed.

See analysis details on SonarQube Cloud

[jlklos]

New code was tested by running Caldera with and without the Manx plugin present. Confirmed agent sessions behaved as expected in each case.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
82.2% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
82.2% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud