feat: support pre-fill forms on the ask page

[hgaol]

close #1009 . + @shuashuai to help to review, thx!

using prefill query parameter for pre-fill content. Using JSON format with same structure with draft data saved in local storage.

the query parameter should be serialized before using as parameter. the serialization steps are similar as below.

encodeURIComponent(JSON.stringify(<object>))

e.g.

http://localhost:3000/questions/ask?prefill=%7B%22title%22%3A%22aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa%22%2C%22tags%22%3A%5B%7B%22slug_name%22%3A%22test%22%2C%22display_name%22%3A%22test%22%2C%22original_text%22%3A%22tst%22%7D%5D%2C%22content%22%3A%22%20wwwwwwwwwwwwwwwwwwww%5Cn%20%5Cn%20%23%20hello%20world!%5Cn%20%5Cn%20%60%60%60js%5Cn%20const%20a%20%3D%201%3B%5Cn%20%60%60%60%22%2C%22answer_content%22%3A%22%22%7D

[hgaol]

the structure is as below.

{
  "title": "wwwwwwwwwwwwwwwww",
  "tags": [
    { "slug_name": "test", "display_name": "test", "original_text": "tst" }
  ],
  "content": "# wwwwwwwwwwwwwwwwwwww\n\nhello world!\n\n```js\nconst a = 1;\n```"
}

[shuashuai]

Discussed some details with the product, from the user's point of view, the current program will bring some difficulty to the user, the specific implementation details I will add to issue #1009

1. the goal should be to simplify the use of the program requires the user to go through a number of technical means to deal with the splicing of parameters, the use of the scenario is restricted.
2. the tags parameter also needs to go through the system's tagging information in order to add tags correctly, which we should simplify here.

[hgaol]

Discussed some details with the product, from the user's point of view, the current program will bring some difficulty to the user, the specific implementation details I will add to issue #1009

1. the goal should be to simplify the use of the program requires the user to go through a number of technical means to deal with the splicing of parameters, the use of the scenario is restricted.
2. the tags parameter also needs to go through the system's tagging information in order to add tags correctly, which we should simplify here.

updated. support pre-fill with markdown format.

e.g.

http://localhost:3000/questions/ask?prefill=---%0Atitle%3A%20hello%20world%0Atags%3A%20feature-request%2C%20template%2Ctest%0A---%0A%0ASome%20body%20text...%0A

[shuashuai]

Thanks.