qcschema_input and qcschema_molecule updating

[loriab]

Description

• From discussion in add schema fields to molecule #59, adds req'd fields {'schema_name': 'qcschema_molecule', 'schema_version': 2} within molecule schema. closes add schema fields to molecule #59 . qcelemental 0.2.7 will understand this as dtype=2.
• Effectively in the QCA software stack, qc_schema_[in|out]put has been moving to qcschema_[in|out]put, so this PR expresses the patterns in regex. Also removes the possibility to say sldkfjsl_qc_schema, which I've never actually seen encoded. Postfix still allowed.

Status

• Ready to go

[loriab]

ok, passing. do squash. and if I've completely messed up the versioned testing by editing the test cases, let me know.

[dgasmith]

Any reason to allow postfix? I think it was always the intent that exact match was required.

[loriab]

postfix is what's allowing qcschema_input and qcschema_output at the moment.

[dgasmith]

The base_schema is an implementation detail in this repo and is overridden per schema molecule/input/output at the moment (or should be). Might be worth removing this line from the base schema.

[loriab]

so long as neither input/output try to validate against base_schema, I think this'll do.

[dgasmith]

LGTM