feat(table): add inline editing + buttons

[atiratree]

Hello,

these are the styles for pf-react Table (patternfly/patternfly-react#1227).

It was inspired by pf3 inline-edit (https://github.com/patternfly/patternfly-react/blob/aa839a80a005f5d540faeb0e1a0320b7df1cc982/packages/patternfly-3/patternfly-react/less/inline-edit.less)

few issues:

• I didn't put the confirmation buttons into the examples because their location is computed (depends on scroll and resize)
• not sure if the colors should be the same as in pf3 (light/dark theme?)
• the borders seem to misbehave in firefox

[atiratree]

this PR has a lower priority and the styles were temporarily moved to pf-react (after a recent discussion)

for future reference: there is a bug in firefox which breaks the table borders: https://bugzilla.mozilla.org/show_bug.cgi?id=688556