Update Sky130 SRAM22 Hammer plugin

[rahulk29]

Update to use the latest version of the Sky130 SRAM22 macros.
This PR updates Hammer to use the latest naming convention and to search for
Liberty files in order of decreasing accuracy.
The script for generating the SRAM cache JSON file has also been updated;
it now scans a local copy of the Sky130 SRAM22 macros repository to find all available SRAMs automatically.

Related PRs / Issues

Type of change:

• Bug fix
• New feature
• Other enhancement

Impact:

• Change to core Hammer
• Change to a Hammer plugin
• Other

Contributor Checklist:

• Did you set master as the base branch?
• Did you state the type-of-change/impact?
• Did you delete any extraneous prints/debugging code?
• (If applicable) Did you add documentation for the feature?
• (If applicable) Did you update the poetry.lock file if you updated the requirements in pyproject.toml?
• (If applicable) Did you add a unit test demonstrating the PR?
• (If applicable) Did you run this through the e2e integration tests?
• (If applicable) Did you update the submodules in e2e/ if this feature depends on updated plugins?