New module bwafastalign-index

[peterpru]

This PR adds the bwa-fastalign index subtool, needed for bwa-fastalign mem. See issue #11835

PR checklist

Closes #XXX

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[peterpru]

Need correct containers/conda and test snapshots.

[ramprasadn]

@nf-core-bot fix linting

[ramprasadn]

@nf-core-bot fix linting