TranscriptVersion page - show whether transcript sequence is different than pasted exons

For instance I think NM_022356.3 is different, as a c. dup is converted to a delins on 1 genome build but not the other

Probably the easiest way to do this is to add some methods onto:

```
genes.hgvs.biocommons_hgvs.data_provider.DjangoTranscriptDataProvider
```

to test eg

```
from genes.models import GenomeBuild, TranscriptVersion
tv = TranscriptVersion.get("NM_022356.3", GenomeBuild.grch38())
tv.sequence_info.sequence
```

Start with genes.hgvs.biocommons_hgvs.data_provider.DjangoTranscriptDataProvider and inspect how TranscriptVersion.get("NM_022356.3", GenomeBuild.grch38()).sequence_info.sequence is exposed to the TranscriptVersion page. Compare the transcript sequence with the pasted exons across genome builds, using NM_022356.3 as the example. Done means the page clearly shows whether the sequences differ.

Written by the indexing model from the issue text.