Consider using less react-bootstrap in favor of regular HTML tags

[estambakio-sc]

Meta-Info	Value
ExtProjectId	JCPROC-01
Original Estimation	???h
Remaining Estimation	???h

While some react-bootstrap components are really useful, other can be removed in favor of regular HTML tags. For example, Form or Button components, which do nothing but render <form> or <button>, but still take ~20kb uncompressed each in codebase. There are probably more such components (FormControl, FormGroup, etc.).

We should consider rewriting components using more pure HTML and less react-bootstrap, if it does save bundle size.

Demo on GH Pages: https://opuscapita.github.io/react-crudeditor/branches/issue-285/?currentComponentName=ContractEditor&maxContainerWidth=100%25&showSidebar=false