Refactor module structure and naming convention

[bosd]

Currently there are 2 modules in this repo, each of them have a lot of dependencies and data.
Some of the data is double. Proposal is to use common odoo practice and perform a clean up by adding a parent base module.

base_monero

The base module will define XMR currency and symbol.
To fix allow to use enough decimal places and optional integration with accounting let it depend on the oca module account_cryptocurrency
Sets up the monero journals.
also have the following dependencies:
account
queue_job
"external_dependencies": {"python": ["monero"]}
It will not depend on web. So it can be used on systems without website installed.

monero-rpc-odoo

monero-rpc-odoo rename to payment_monero
Depends on the base_monero module.

monero-rpc-odoo-pos

monero-rpc-odoo-pos rename to pos_payment_monero
Depends on the base_monero module.
Remove the field is_cryptocurrency, as it is unused.
(maybe implement a hook to recalulate the exchange rate.)
"category": "Accounting" to 'category': 'Sales/Point of Sale'

account_monero_transfer

Future module to be developed to initiate a monero payment from the odoo backend to a supplier?
Will also depend on base monero.
Depends on the base_monero module.

edit:
since the monero lib is used instead of monero-rpc.
Change the names to prevent confusion.

[bosd]

@AdriaGForgeFlow Since you're the author of the module account_cryptocurrency can you share your knowledge how to integrate monero with this module?

[bosd]

@JordiBForgeFlow your knowledge on this subject is appreciated :)