Improvements to the Companies House ETL

[giacecco]

Change the ETL to implement everything that has been defined in:

• Review of Alpha components (what can be kept, what needs being re-done), includes implementation / addressing issues / non-functional improvements (incl. performance) #1
• More rigorous testing strategy definition and tools #2
• Confidence - Research and statistical model definition  #3
• Revised data model - Full support of addresses' "time validity" #4
• Revised data model - Management of "negative information" #5 (probably doesn't apply)
• Revised ETL model - Evaluation of Turbot as hosting platform #7
• Cross-edition (or "memory") inference (ETL-level) #8
• Revised ETL model - Support for deep archiving of sources #10
• Review of provenance model #11 including 'live' provenance (was hard-coded in Alpha)
• Revised ETL model - Scheduler support #20
• and to use Re-usable free-text addresses interpreter, "service" and ETL for OA website  #15 rather than having its own implementation.

[peterkwells]

Shifting back one sprint