📘 [Format] Add possibility to upload own dictionaries

[camarm-dev]

This represents a lot of job... We need to convert the source dictionary to a compatible format. Two options: first converting it to a intermediary format, and then to a Remède database / directly convert to a Remède database (but need to create a universal converter...)

pyglossary will be useful to do this. Maybe the simplest way is to upload the source dictionary to a converter server.

• TODO: Find multiple interesting formats

[camarm-dev]

The best solution is to create a service that can convert any dictionary to the Remède format, using pyglossary. Then the users upload his dictionary and download its Remède format, to be used in offline mode.