Add more chain peptides from Uniprot xml protein processing info

[blfrey]

Discovered this issue in MetaMorpheus top-down for bovine cationic trypsin (P00760), which has a signal peptide (1-17), a propeptide (18-23), and a chain peptide (24-246). Actual trypsinogen from Sigma is the chain 18-246 (i.e. 2 of the 3 segments), but this is not parsed as an option by mzlib for Metamorpheus top-down to use. It seems that mzlib allows the entire length (1-246) and the three smaller segments individually, but not the combination of 2 of the segments.

Note that this also could be relevant to bottom-up b/c imagine an enzymatic digest of trypsinogen (18-246), which could have an N-terminal peptide that spans 18-32. That probably wouldn't be assigned currently b/c mzlib isn't allowing this protein sequence to start at position 18.

In this case of P00760, mzlib should parse it to allow:
1-246, full-length
1-17, signal peptide
18-23, pro-peptide
24-246, chain peptide
1-23, signal+propeptide
18-246, propeptide+chain

Some proteins with even more segments (e.g Glucagon) will have many more combinations.