[Fr] Fixes

Hello,

I'm a French-Italian student in an engineering school, web developer for 5 years and I use CI on my personal and professional projects.
I wanted to check the progression of the French translation and I noticed some tiny mistakes, so I figured I had to help you with that.

Here are the explanations for the fixes. They don't include typos (Accents, wrong letters). Some are debatable, and new ones can be found this way.

date_: 
- 42. The string is the same as the next one, so I linked both ;
- Aligned "=" chars ;
- Used the same quote format for each string (double) ;
- Aligned UTC hours for consistence purposes.

db_: 
- "fournir", "passer en paramètre", "indiquer" are sometimes better, contextually speaking, than "soumettre", which is usually employed for form submission ;
- "supporter" is better than "soumettre", when the meaning is related to feature support ;
- We don't say "colonne" that much in French, when talking about a table field. "Champ" is more accurate.

email_:
- In French typography, you have to put spaces before and after complex punctuation (colon, semicolon, exclamation mark, interrogation mark, etc.).

form_validation_:
- "Integer" is not user-friendly. "Nombre entier" is more likely to be understood.

migration_:
- Zero is considered singular. Plural forms are not justified here.

number_:
- French translation for [KMGT]B is [KMGT]o.

upload_:
- Talking about possibility is better than capability for a non-human/physical object.


Remember that these fixes are totally debatable, and my pull request is just a suggestion.

Thank you.
- Vincenzo S.