Pull Metadata from Plugin during init #60

Epic: #53

when new project is init'ed and user specifies the db plugin to use, dbpatch should interogate the plugin for certain types of information
For Example:

• what is the file extension(s) used for patch and code files
• what is the ordered list of files to default to in patches.json for what code files to execute and in what order.
• any additional options that the plugin supports but are not part of the default dbpatch configuration; we could add these to patches.json

(or re-init'ed if we allow that for example if user changes or sets plugin from what was done first time)