Updated bedbase ids and docs

[khoroshevskyi]

Changes:

• Updated readme file - updated bedbase links with correct bed files ids

[mdozmorov]

@khoroshevskyi, thank you, that was long overdue. Before merging, can you correct several links that return "Not found"? https://bedbase.org/bed/ and https://bedbase.org/docs/v1

[khoroshevskyi]

@mdozmorov, I fixed incorrect links and added 2 missing files,
Additionally FYI, ['hg19.UCSC.scaffold', 'mm10.UCSC.scaffold', 'mm10.UCSC.fragment'] files are missing in google drive, and I couldn't add them to the BEDbase

[mdozmorov]

Thank you! I'll get in touch about the missing files, we have 8 more to add.