renamed sidebar entry `Fixed` to `Fixed Sidebar` & renamed file `fixed.html` to `fixed-sidebar.html`

- removed js margin-top/-bottom generation
- added layout-navbar-not-fixed & layout-footer-not-fixed incl. responsive variants (eg. layout-*-navbar-not-fixed, layout-*-footer-not-fixed)
- added responsive variants for fixed (eg. layout-*-navbar-fixed, layout-*-footer-fixed)
- added default border-bottom to main-header navbar like main-footer
- removed .border-bottom from main-header navbar in demo pages

- updated DataTables typo in demo files
- added jsGrid to package,json & npm/Plugins.js
- added jsgrid demo

- created project_add & project_edit
- updated project_detail
- added menu link to all demo files
- added a line break in _colors.scss

- created contacts demo page
- removed unnecessary scss classes (.hide, .no-border, .no-shadow, .flat & .list-unstyled)
- updated demo files to use bootstrap's class instead of old unnecessary class
- moved color scss lines in a seperate scss file (_colors)
- moved old plugin fixes in a new scss file (plugins/_miscellaneous)

- updated _navs.scss with tabs override css
- added pages/UI/navbar demo with navbar color examples & vertical tabs example
- added navbar & tabs sidebar entry in demo files with sidebar

- added sweetalert2 & toastr to package.json & build/npm/Plugins.js
- added plugin related scss fixes and created files per plugin
- updated "Modals" demo page to "Modals & Alerts" & renamed link on all demo files
- rebuild dist files

- added scss lines form @BruceHill
- created pages/examples/legacy-user-menu.html as single page demo with html code from @BruceHill but with some modifications ;)
- updated demo files, added legacy user menu link in Extras after Starter Page
- rebuild dist files

- replaced slimScroll to overlayScrollbars
- added new layout types (fixed, navbar-fixed & footer-fixed)
- changed old default layout from "fixed" to non-fixed
- enhanced PushMenu.js to load options via data
- enhanced Layout.js new layout calcs, options via data for scrollbar
- fixed forms fontawesome icons
- added warning-feedback (without icon)
- added sidebar-mini-md
- updated index to use layout-fixed
- updated index2 to use layout-fixed, layout-navbar-fixed & layout-footer-fixed

- replaced `fas fa-circle-o` with `far fa-circle`

- fixed fontawesome icon rules in buttons, cards, sidebar & smallbox
- added calc for `.content-wrapper` min-height
- added layouts: top-nav, boxed & sidebar collapsed
- fixed mailbox attachment size
- added bg-*, navbar-*
- updated demo.js
- updated sidebar in demo files (added layout options)
- added autoprefixer to fix browser specific css changes
- added css sourcemap for adminlte.min.css

- updated all demo pages
- updated fontawesome entries in build/npm/Plugins
- updated package.json & package-lock.json
- replaced fontawesome files in plugins/

- added Modals Demo Page
- added Link to Modals in any other Demo Page
- added Modal Color Variation fixes
- updated zindex values `header` from 1000 to 900 `sidebar` from 1100 to 950 (below bootstrap 4 defaults to work with dropdown, modal, popover & tooltip)
- removed tooltip zindex overide