Rule-based French Lemmatizer (#2818)

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## Description
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Add a rule-based French Lemmatizer following the english one and the excellent PR for [greek language optimizations](#2558) to adapt the Lemmatizer class.

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- Lemma dictionary used can be found [here](http://infolingu.univ-mlv.fr/DonneesLinguistiques/Dictionnaires/telechargement.html), I used the XML version.
- Add several files containing exhaustive list of words for each part of speech 
- Add some lemma rules
- Add POS that are not checked in the standard Lemmatizer, i.e PRON, DET, ADV and AUX
- Modify the Lemmatizer class to check in lookup table as a last resort if POS not mentionned
- Modify the lemmatize function to check in lookup table as a last resort
- Init files are updated so the model can support all the functionalities mentioned above
- Add words to tokenizer_exceptions_list.py in respect to regex used in tokenizer_exceptions.py

## Checklist
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- [X] I have submitted the spaCy Contributor Agreement.
- [X] I ran the tests, and all new and existing tests passed.
- [X] My changes don't require a change to the documentation, or if they do, I've added all required information.

spacy/lang/fr/__init__.py

@@ -6,7 +6,8 @@
 from .tag_map import TAG_MAP
 from .stop_words import STOP_WORDS
 from .lex_attrs import LEX_ATTRS
-from .lemmatizer import LOOKUP
+from .lemmatizer import LEMMA_RULES, LEMMA_INDEX, LEMMA_EXC, LOOKUP
+from .lemmatizer.lemmatizer import FrenchLemmatizer
 from .syntax_iterators import SYNTAX_ITERATORS
 
 from ..tokenizer_exceptions import BASE_EXCEPTIONS
@@ -28,7 +29,16 @@ class FrenchDefaults(Language.Defaults):
     suffixes = TOKENIZER_SUFFIXES
     token_match = TOKEN_MATCH
     syntax_iterators = SYNTAX_ITERATORS
-    lemma_lookup = LOOKUP
+
+
+    @classmethod
+    def create_lemmatizer(cls, nlp=None):
+        lemma_rules = LEMMA_RULES
+        lemma_index = LEMMA_INDEX
+        lemma_exc = LEMMA_EXC
+        lemma_lookup = LOOKUP
+        return FrenchLemmatizer(index=lemma_index, exceptions=lemma_exc,
+                                rules=lemma_rules, lookup=lemma_lookup)
 
 
 class French(Language):