feat: ensembl reference collections

[mauripops]

feat: collections optional reference parameter(i.e. bacterial references)

This PR builds on the recently pushed (#2928) where branches and specific url can be defined as parameters. The previous method was unable to find data from bacteria ensembl due to data in it containing one more folder level. There is also a fix for the spec variable in in ensembl-sequence where the release version would not match for branches other than the default.

QC

• I confirm that:

For all wrappers added by this PR,

• there is a test case which covers any introduced changes,
• input: and output: file paths in the resulting rule can be changed arbitrarily,
• either the wrapper can only use a single core, or the example rule contains a threads: x statement with x being a reasonable default,
• rule names in the test case are in snake_case and somehow tell what the rule is about or match the tools purpose or name (e.g., map_reads for a step that maps reads),
• all environment.yaml specifications follow the respective best practices,
• the environment.yaml pinning has been updated by running snakedeploy pin-conda-envs environment.yaml on a linux machine,
• wherever possible, command line arguments are inferred and set automatically (e.g. based on file extensions in input: or output:),
• all fields of the example rules in the Snakefiles and their entries are explained via comments (input:/output:/params: etc.),
• stderr and/or stdout are logged correctly (log:), depending on the wrapped tool,
• temporary files are either written to a unique hidden folder in the working directory, or (better) stored where the Python function tempfile.gettempdir() points to (see here; this also means that using any Python tempfile default behavior works),
• the meta.yaml contains a link to the documentation of the respective tool or command,
• Snakefiles pass the linting (snakemake --lint),
• Snakefiles are formatted with snakefmt,
• Python wrapper scripts are formatted with black.
• Conda environments use a minimal amount of channels, in recommended ordering. E.g. for bioconda, use (conda-forge, bioconda, nodefaults, as conda-forge should have highest priority and defaults channels are usually not needed because most packages are in conda-forge nowadays).