Add annotation (GFF/BED) stats reporting.

[jfy133]

Is your feature request related to a problem? Please describe.
In some cases one maybe interested not just the overall coverage of the entire reference, but also of specific genes, the positions of which are typically defined in BED or GFF format.

Describe the solution you'd like
Include a module that uses e.g. bedtools to create summary stats for each region in the GFF/BED file.

Additional context
Note that bedtools output cannot be used for MultiQC due to a lack if stanardised and identifiable log/output file suffix

[jfy133]

https://bedtools.readthedocs.io/en/latest/content/tools/coverage.html

For reference

[jfy133]

This can also be helpful for the competitive mapping issue referred to here #21

Whereby if we wanted to make competitive mapping properly as a 'feature' of EAGER2, we auto generate a bedfile when concatenating multiple-fastas of the coordinates of each FASTA in the superrefernece.

A user can still manually create this reference and bed file and supply it to EAGER, if we decide not to make an 'inbuilt' feature.