Feature: basic requirements validation

[stanislaw]

Requirement:

• [ ] Requirement's title must not end with a dot.
• [ ] Requirement UID does not match a containing document/section's requirement prefix.
• [ ] Requirement must have a parent (unless a document is a root document).
• [ ] Requirement must have a rationale.
• [ ] Requirement statement must have a "shall"/"may" or other words (TBD standardize).
• [ ] Requirement has a TBD/TBC.
• [ ] Requirement has typos.

Document:

• [ ]