Fix miscellaneous issues with components

[dpvc]

This PR makes miscellaneous updates to various component configurations and related changes.

• A ui/menu dependency on a11y/sre is added (since SpeechMenu.ts uses it).
• The output/chtml and output/svg config files now target common.ts, so that that will be included in the MathJax._ tree, and the components/src/startup/lib is added so that ts/components/package.ts will be shared properly. (Otherwise this leads to two separate copies of the Package class that don't know about what the other one has loaded.)
• The webpack.common.js and package.json are modified to allow compoments/js to obtain compoments/mjs or components/cjs depending on whether it is used in an import or a require(). (The older components/src is still there for backward compatibility with v3, before we had the mjs/cjs split).
• The global.ts file is modified to check that the MathJax variable is actually an object literal, rather than a string or array or some other thing.
• The all-packages component is remove from the \require list, since that component was removed in a previous PR.

[zorkow]

lgtm.