Converting src/middleware/helpers.js from JS to TS

[VinayManukonda3321]

This pull request converts src/middleware/helpers.js from JS to TS. This resolves #107

The changes I made are the following: 1.Created a new ts file named helper.ts in src/middleware 2.Made some minor changes in the following files src/controllers 404.js errors.js helpers.js src/middleware admin.js assert.js header.js headers.js helpers.js(changes are automatically made) index.js maintenance.js render.js uploads.js user.js

In TypeScript, when you have explicit type information, you need to use .default to access the default export. So, made the necessary changes in import statement in all the above files.

[coveralls]

Pull Request Test Coverage Report for Build 7720790076

• 0 of 52 (100.0%) changed or added relevant lines in 13 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.002%) to 85.091%

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Files with Coverage Reduction	New Missed Lines	%
src/middleware/helpers.js	1	93.98%
<!--	Total:	1		-->

Totals
Change from base Build 7649102120:	-0.002%
Covered Lines:	22626
Relevant Lines:	25353

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💛 - Coveralls

[VinayManukonda3321]

while the linter expects LF (Line Feed) line endings all my file has CRLF (Carriage Return + Line Feed) line endings which resulted in failing a check.