Remove parameter database and depend on {epiparameterDB}

[joshwlambert]

This PR splits the {epiparameter} code and data by removing the epidemiological parameter database from the package and instead depending on the new {epiparameterDB} package that stores and distributes the epiparameters that previously were in the {epiparameter} package.

Changes include:

• remove parameter.json and data_dictionary.json
• remove validate-json.yaml workflow
• removing the CC0 data license from the LICENSE file
• removing {jsonlite} as suggested dependency
• remove sysdata
• update functions that called sysdata to use .read_epiparameter_db()
• update .read_epiparameter_db() to call epiparameterDB::epiparameterDB
• remove .is_pkg_installed()
• remove unit tests for functions that are removed
• update dependency documentation in design_principles.Rmd vignette

[github-actions]

This pull request:

• Adds 1 new dependencies (direct and indirect)
• Adds 1 new system dependencies
• Removes 0 existing dependencies (direct and indirect)
• Removes 0 existing system dependencies

Reach out on slack (#code-review or #help channels) to double check if there are base R alternatives to the new dependencies.

(Note that results may be inaccurate if you branched from an outdated version of the target branch.)

[github-actions]

This pull request:

• Adds 1 new dependencies (direct and indirect)
• Adds 1 new system dependencies
• Removes 0 existing dependencies (direct and indirect)
• Removes 0 existing system dependencies

Reach out on slack (#code-review or #help channels) to double check if there are base R alternatives to the new dependencies.

(Note that results may be inaccurate if you branched from an outdated version of the target branch.)