[v1.4] Support text-separator customization

[Clémentine]

Following this central issue

• Add two new settings: separatorTokens and nonSeparatorTokens with get, update, and reset methods associated.
  Here are the JS equivalents in meilisearch-js you should create for this repository:

client.index('indexName').getSeparatorTokens(); // calls GET /indexes/:uid/settings/separator-tokens
client.index('indexName').updateSeparatorTokens(['|', '/', '&sep']);  // calls PUT /indexes/:uid/settings/separator-tokens
client.index('indexName').resetSeparatorTokens(); // calls DELETE /indexes/:uid/settings/separator-tokens

client.index('indexName').getNonSeparatorTokens(); // calls GET /indexes/:uid/settings/non-separator-tokens
client.index('indexName').updateNonSeparatorTokens(['@', '#']); // calls PUT /indexes/:uid/settings/non-separator-tokens
client.index('indexName').resetNonSeparatorTokens(); // calls DELETE /indexes/:uid/settings/non-separator-tokens

• The methods associated with the /settings API route (to get, reset and update the settings globally) must be able to receive in the payload the two new configurations separatorTokens and nonSeparatorTokens
• ⚠️ Add integration tests ⚠️
• Update the .code-samples.meilisearch.yaml
  • Add get_separator_tokens_1 key and “translate” the following curl example by using the newly added methods: https://github.com/meilisearch/documentation/blob/2060089a5c10bcd0beb28633062f90cf0b279f7f/.code-samples.meilisearch.yaml#L1111
  • Add update_separator_tokens_1 key and “translate” the following curl example by using the newly added methods: https://github.com/meilisearch/documentation/blob/2060089a5c10bcd0beb28633062f90cf0b279f7f/.code-samples.meilisearch.yaml#L1114
  • Add reset_separator_tokens_1 key and “translate” the following curl example by using the newly added methods: https://github.com/meilisearch/documentation/blob/2060089a5c10bcd0beb28633062f90cf0b279f7f/.code-samples.meilisearch.yaml#L1119
  • Add get_non_separator_tokens_1 key and “translate” the following curl example by using the newly added methods: https://github.com/meilisearch/documentation/blob/2060089a5c10bcd0beb28633062f90cf0b279f7f/.code-samples.meilisearch.yaml#L1122
  • Add update_non_separator_tokens_1 key and “translate” the following curl example by using the newly added methods: https://github.com/meilisearch/documentation/blob/2060089a5c10bcd0beb28633062f90cf0b279f7f/.code-samples.meilisearch.yaml#L1125
  • Add reset_non_separator_tokens_1 key and “translate” the following curl example by using the newly added methods: https://github.com/meilisearch/documentation/blob/2060089a5c10bcd0beb28633062f90cf0b279f7f/.code-samples.meilisearch.yaml#L1130