Issue 92 Rename API Paramaters to API Options and also port in Custom Data Documentation to help with Issue 92

https://wiki.civicrm.org/confluence/display/CRMDOC/Database+layer

(so that we can avoid a broken link in a wiki page we're migrating)

ref:
https://docs.civicrm.org/dev/en/latest/documentation/style-guide/#parts-chapters-sections

https://wiki.civicrm.org/confluence/display/CRMDOC/Add-on+Formats

https://wiki.civicrm.org/confluence/display/CRMDOC/Cache+Reference

Auto-import with no edits

from:
https://wiki.civicrm.org/confluence/display/CRMDOC/API+Architecture+Standards

Direct import (no modifications).

Reorder requirements docs into the basics section and move devloping civicrm into core and add backdrop in

Reorder extensions files and rename to be extension structure to be clear its more than just files its directory strcutre and improve doc a bit