Replace std::bind with lambdas

[ranisalt]

Pull Request Prelude

• I have followed proper The Forgotten Server code styling.
• I have read and understood the contribution guidelines before making this PR.
• I am aware that this PR may be closed if the above-mentioned criteria are not fulfilled.

Changes Proposed

std::bind is bad for several reasons:

• The code is not really clear, the usage of placeholders makes it difficult to follow
• The complexity of the implementation of std::bind often results in sub-optimal code
• The possibilities offered by bind are limited, for instance, it’s not possible to bind a function with variable arguments allows to silently discard some arguments, which is often not what was expected - see in connection.cpp how in some calls it simply ignored a parameter, with lambdas we have to write the proper callback param types
• Fixed arguments are evaluated when bind is called, not when the bound function is called, which might be surprising in some cases - it is also considerably slower to compile
• bind requires to take the address of a function, which can be difficult (if the function is overloaded) or not recommended (for standard library functions)

(source)

See also detailed explanation by Jason Turner.

Additionally, move non-trivial types into lambdas to avoid expensive copies for temporary values, and used lambdas where we tried to work around std::bind's lack of flexibility.

[MillhioreBT]

problem solved with Fix potential bad weak_ptr usage commit

Sorry to bother but I've been testing the changes a bit more and I ran into a problem, I don't know if it's due to my custom sources or if this could also be happening in TFS.

Everything compiles successfully, you can even enter with any player, however when disconnecting the player this error can happen, when I place a breakpoint here it increases the probability that the error will not occur

Note: In fact, if I do it, I go through the interruption points very slowly, clicking the Continue button every 5 seconds or more, there is no problem.
But when I hit the continue button quickly the problem occurs
This is what happens when I loop through the breakpoints quickly:

Basically the call stack is as follows:

ProtocolGame::logout
Protocol::disconnect
Connection::close
and then the call to
ProtocolGame::release() in lambda g_dispatcher.addTask(createTask([=]() { protocol->release(); }));
finally the error seems to occur on this call
OutputMessagePool::getInstance().removeProtocolFromAutosend(shared_from_this());

[DSpeichert]

Overall, I feel like we should have a style where the lambda body is always on its own lines, some of those "short" one-liners are actually long eye sores, is there a formatting standard we can adopt, since lambdas are not common in the codebase yet?

[ranisalt]

@DSpeichert that's definitely what I'm doing next. I spoke to @EPuncker about a standard code style + static analysis + unit testing, however that would be a separate PR