## Summary
This PR is the base implementation of the Terminal Service Class, containing the skeleton structure for #2711.
## Test process
Future me's problem - see #2714
## Checklist
- [X] PR is linked to a **work item**
- [X] **acceptance criteria** of linked ticket are met
- [X] performed **self-review** of the code
- [ ] written **tests** for any new functionality added with this PR
- [] updated the **documentation** if this PR changes or adds functionality
- [ ] written/updated **design docs** if this PR implements new functionality
- [X] updated the **change log**
- [X] ran **pre-commit** checks for code style
- [ ] attended to any **TO-DOs** left in the code
Related work items: #2711
## Summary
Refactor of `DatabaseClient` and `DatabaseService` to update how connection IDs are generated. These are now provided by DatabaseService when establishing a connection.
Creation of `DatabaseClientConnection` class. This is used by `DatabaseClient` to hold a dictionary of active db connections.
## Test process
Tests have been updated to reflect the changes and all pass
## Checklist
- [X] PR is linked to a **work item**
- [X] **acceptance criteria** of linked ticket are met
- [X] performed **self-review** of the code
- [X] written **tests** for any new functionality added with this PR
- [X] updated the **documentation** if this PR changes or adds functionality
- [ ] written/updated **design docs** if this PR implements new functionality
- [X] updated the **change log**
- [X] ran **pre-commit** checks for code style
- [X] attended to any **TO-DOs** left in the code
Related work items: #2462
## Summary
*Replace this text with an explanation of what the changes are and how you implemented them. Can this impact any other parts of the codebase that we should keep in mind?*
## Test process
*How have you tested this (if applicable)?*
## Checklist
- [Y] PR is linked to a **work item**
- [Y] **acceptance criteria** of linked ticket are met
- [Y ] performed **self-review** of the code
- [N] written **tests** for any new functionality added with this PR
- [Y] updated the **documentation** if this PR changes or adds functionality
- [N] written/updated **design docs** if this PR implements new functionality
- [N] updated the **change log**
- [Y] ran **pre-commit** checks for code style
- [N] attended to any **TO-DOs** left in the code
Related work items: #2068
