[Frontend] Styling for controls

Fixes #1324
CSS, markup, new glyphs for
brightness and contrast

platform/commonUI/general/res/fonts/symbols/openmct-symbols-16px.svg

@@ -73,6 +73,8 @@
 <glyph unicode="&#xe1034;" glyph-name="icon-two-parts-both" d="M896 960h-768c-70.4 0-128-57.6-128-128v-768c0-70.4 57.6-128 128-128h768c70.4 0 128 57.6 128 128v768c0 70.4-57.6 128-128 128zM128 832h320v-768h-320v768zM896 64h-320v768h320v-768z" />
 <glyph unicode="&#xe1035;" glyph-name="icon-two-parts-one-only" d="M896 960h-768c-70.4 0-128-57.6-128-128v-768c0-70.4 57.6-128 128-128h768c70.4 0 128 57.6 128 128v768c0 70.4-57.6 128-128 128zM896 64h-320v768h320v-768z" />
 <glyph unicode="&#xe1036;" glyph-name="icon-x-in-circle" d="M512 960c-282.8 0-512-229.2-512-512s229.2-512 512-512 512 229.2 512 512-229.2 512-512 512zM832 256l-128-128-192 192-192-192-128 128 192 192-192 192 128 128 192-192 192 192 128-128-192-192 192-192z" />
+<glyph unicode="&#xe1038;" glyph-name="icon-brightness" d="M253.414 641.939l-155.172 116.384c-50.233-66.209-85.127-146.713-97.91-234.39l191.586-30.216c8.145 56.552 29.998 106.879 62.068 149.006zM191.98 402.283l-191.919-27.434c13.115-90.459 48.009-170.963 99.174-238.453l154.18 117.665c-31.476 41.347-53.309 91.675-61.231 146.504zM466.283 768.020l-27.434 191.919c-90.459-13.115-170.963-48.009-238.453-99.174l117.665-154.18c41.347 31.476 91.675 53.309 146.504 61.231zM822.323 861.758c-66.209 50.233-146.713 85.127-234.39 97.91l-30.216-191.586c56.552-8.145 106.879-29.998 149.006-62.068zM832.020 493.717l191.919 27.434c-13.115 90.459-48.009 170.963-99.174 238.453l-154.18-117.665c31.476-41.347 53.309-91.675 61.231-146.504zM201.677 34.242c66.209-50.233 146.713-85.127 234.39-97.91l30.216 191.586c-56.552 8.145-106.879 29.998-149.006 62.068zM770.586 254.061l155.131-116.343c50.233 66.209 85.127 146.713 97.91 234.39l-191.586 30.216c-8.125-56.564-29.966-106.906-62.028-149.049zM557.717 127.98l27.434-191.919c90.459 13.115 170.963 48.009 238.453 99.174l-117.665 154.18c-41.347-31.476-91.675-53.309-146.504-61.231zM770.586 448c0-142.813-115.773-258.586-258.586-258.586s-258.586 115.773-258.586 258.586c0 142.813 115.773 258.586 258.586 258.586s258.586-115.773 258.586-258.586z" />
+<glyph unicode="&#xe1039;" glyph-name="icon-contrast" d="M512 960c-282.78 0-512-229.24-512-512s229.22-512 512-512 512 229.24 512 512-229.22 512-512 512zM783.52 176.48c-69.111-69.481-164.785-112.481-270.502-112.481-0.358 0-0.716 0-1.074 0.001l0.055 768c212.070-0.010 383.982-171.929 383.982-384 0-106.034-42.977-202.031-112.462-271.52z" />
 <glyph unicode="&#xe1100;" glyph-name="icon-activity" d="M576 896h-256l320-320h-290.256c-44.264 76.516-126.99 128-221.744 128h-128v-512h128c94.754 0 177.48 51.484 221.744 128h290.256l-320-320h256l448 448-448 448z" />
 <glyph unicode="&#xe1101;" glyph-name="icon-activity-mode" d="M512 960c-214.866 0-398.786-132.372-474.744-320h90.744c56.86 0 107.938-24.724 143.094-64h240.906l-192 192h256l320-320-320-320h-256l192 192h-240.906c-35.156-39.276-86.234-64-143.094-64h-90.744c75.958-187.628 259.878-320 474.744-320 282.77 0 512 229.23 512 512s-229.23 512-512 512z" />
 <glyph unicode="&#xe1102;" glyph-name="icon-autoflow-tabular" d="M192 960c-105.6 0-192-86.4-192-192v-640c0-105.6 86.4-192 192-192h64v1024h-64zM384 960h256v-1024h-256v1024zM832 960h-64v-704h256v512c0 105.6-86.4 192-192 192z" />