SEC-131 - CollectionOfSecurityPrices needs work

[ElisaKendall]

Signed-off-by: Elisa Kendall ekendall@thematix.com

Description

Removed redundant restrictions on CollectionOfSecurityPrices and loosened the constraint on PriceStructure saying that it had to include quoted prices only

Fixes: #1837 / SEC-131

Checklist:

• [x] I'm familiar with the FIBO developer quide. My contribution meets all the requirements described there.
• [x] My contribution follows the principles of best practices for FIBO.
• [x] My changes have been reconciled with latest master and no merge conflicts remain.
• [x] This PR is related to exactly one issue. The issue is referenced by using a GitHub keyword such as "fixes", "closes", or "resolves".
• [x] Hygiene tests have been applied by a PR with "(WIP)" in title.
• [x] The issue has been tested locally using a reasoner (for ontology changes).