Replacing "student" with something else

[chriscool]

Now that the GSoC isn't only for students, it seems to me that we should try to replace "student" in some of our docs with something else, maybe "applicant".

From a quick grep, it looks like our use of "student" is problematic in:

• General-Application-Information.md
• General-Microproject-Information.md
• Mentoring-Program-Guide.md
• SoC-2022-Ideas.md

I think it's ok to leave it in old docs, like docs related to previous GSoCs though.

[chriscool]

Done for General-Microproject-Information.md in e60cb5026d86e3000abe1c21f93d1f867aedac3a with the following explanation:

    The GSoC is now open to people who are not student, so it's better
    if we standardize on using "applicant" for people not yet accepted
    in the GSoC or Outreachy, and on using "contributor" as Google does
    for people accepted in the GSoC.

[chriscool]

I have just done for Mentoring-Program-Guide.md in 1c48446db0c80ea7b3ec82d069ef8c4af3baecea and for General-Application-Information.md in ed9ba757cbf92760265f38d2890ad11fcbd189c4.

I think we can close this as it's not worth it to do it for SoC-2022-Ideas.md and other old docs.