Added explicit form type casting.

[wadamek65]

This PR introduces casting of all form types explicitly across all themes where previously they were typed as any due to TS constraints.

[codecov]

Codecov Report

Merging #1003 (f10491d) into master (8dd2d74) will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1003   +/-   ##
=======================================
  Coverage   98.98%   98.98%           
=======================================
  Files         202      202           
  Lines        3150     3150           
  Branches      796      796           
=======================================
  Hits         3118     3118           
  Partials       32       32           

Impacted Files	Coverage Δ
packages/uniforms-antd/src/AutoForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-antd/src/BaseForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-antd/src/QuickForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-antd/src/ValidatedForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-bootstrap3/src/AutoForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-bootstrap3/src/BaseForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-bootstrap3/src/QuickForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-bootstrap3/src/ValidatedForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-bootstrap4/src/AutoForm.tsx	100.00% <100.00%> (ø)
packages/uniforms-bootstrap4/src/BaseForm.tsx	100.00% <100.00%> (ø)
... and 18 more

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[radekmie]

It is definitely better than it was now. However, we'd need to prepare solid and clear documentation of the change, including workarounds (if needed).

[wadamek65]

@radekmie I'd be happy to add the documentation within this PR if you could provide a little more details on where it should be.

[radekmie]

1. A short comment for the CHANGELOG.md about this change in general.
2. A note in the FAQ section, on what to do when these typings actually broke somebody's code (i.e., cast to any and report us a bug).

[wadamek65]

@radekmie I've added some docs in the FAQ section. I suppose it will be a good basis for when the changelog is actually created or should I also prepare this and put it somewhere right now?