Fix Memory Exhaust Issue

Issue Discription:

with an incoming http requests the server will allocate memory as long as it recieves Data from the incoming Connection even if a MaxUploadSize was defined. This behaviour will trigger a bad_alloc exception then the server host runs out of memory and the server application will terminate. A example would be you upload a 1GB File via a POST request to a server with 512 MB of Memory and no swap.

Issue Fix:

append incoming Data to the content buffer only as long as its size is smaller than maxUploadFile. Otherwise throw away the Data and than return a Status 403 page

Pull Request Checklist

Please check if your Pull Request fulfills the following requirements:

[x] The commit message has a detailed description of the modifications
[ ] Tests for the changes have been added (for bug fixes / features)
[ ] Docs have been added / updated (for bug fixes / features)

Pull Request Type

What kind of change does this Pull Request introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other (Please describe)

What is the current behavior?

Issue Number: N/A

What is the new behavior?

Does this Pull Request introduce a breaking change?

[ ] Yes
[ ] No

HerikLyma / CPPWebFramework