Improve and expand "Faq" page

Some of the questions on the Faq page are outdated or have no reason to exist. I think we can massively improve it.

Best way to start would be to separate all questions in categories and remove obsolete questions like the one about Kovri, or "what is a mnemomonic seed?" <- For the latter a more genereic question could be created. For example:

Q What does this tecnical word mean?
A Check out the <a href="link_to_moneropedia">Moneropedia</a> for an overview of the technial word used in Monero and their meaning.

I also think would be good to have an input from community and contributors on reddit and other platform. I think togheter we can build a very great pool of questions/answers.

Examples of questions that we read almost every day:

• Is it dangerous to run a personal node?
• Is it dangerous to use a remote node? what's the data a node operator can get from me?
• What is the difference between a full node and a node? (Looks like many get confused by this)
• What are the advantages and disadvantages in using a remote node?
• Can't see funds. Did i just lose all my Monero?
• Does Monero have this or that feature?

In general, all present questions/answers should be updated and links pointing to the related section of the website should be added.

I would also like to get rid of the Stack Exchange questions in the hangout page and "move them" in the faq section, since, as correctly said in this comment, they have no reason to be there. I will open another issue about this tho.

I will try to take care of this myself, but i don't know when i will be able to get to it. If anybody is willing to help please comment here or PM me, so that we can work on this together.